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PubMed1987

A study of the lipid transport system in the cat, Felix domesticus.

Feline serum lipoproteins were fractionated into four distinct classes by density gradient ultracentrifugation and characterized with respect to physical and chemical properties. The distribution of serum lipids, lipoproteins and apolipoproteins was quite unlike that in man, the cat having five times as much high density lipoproteins (HDL) as low density lipoproteins (LDL). The lipoproteins in the d less than 1.019 g/ml fraction of cats were larger and were richer in triglycerides than their human counterparts and contained a considerable amount of beta-migrating particles. The low density lipoproteins of cats and man had similar chemical composition, but cat LDL had a higher negative charge, were smaller and contained apoprotein A-I. Cat HDL consisted of two distinct subfractions HDL2 and HDL3 with similar density boundaries and particle size as in man. In cat serum and HDL fraction apoprotein A-II was a minor component. Like human serum, fasting cat serum contained only the larger species of apoprotein B, apo B-100, whereas intestinal lymph contained exclusively the smaller apo B-48. Post heparin feline and human plasma possessed both lipoprotein lipase and hepatic lipase. Chylomicrons formed after a fat load in cats were removed from the circulation as rapidly as in man. It is concluded, that the cat is another animal model of potential interest for the study of lipoprotein metabolism.

Animals↗
PubMed1984

Inter and intratrial variation in cat locomotor behavior.

Four cats were trained to locomote on a treadmill at a variety of speeds. The cats were then filmed at weekly intervals for three weeks; additionally, one of the cats was filmed 35 days prior to the first weekly filming. The films were used to characterize the variation exhibited by the cats in total cycle and swing/stance durations, and in footfall patterns both across the weekly trials and within them, and across speeds. The intertrial comparison indicated the existence of a "training effect" (i.e., a consistent change in gait subsequent to continued training) for only one cat; the cat showed notable reductions in cycle duration at all speeds over time. The intertrial comparison also indicated that a limb (especially a forelimb) could exhibit slightly different (but internally consistent) footfall patterns during different trials. Furthermore, the variation in one forelimb's pattern was usually associated with corresponding, but reciprocal, variation in the other forelimb's pattern. The analysis comparing variation in cycle duration across speeds indicated generally more variability at slow speeds relative to fast speeds. However, maximum or near maximum variability in cycle duration as well as in footfall pattern often occurred at an intermediate speed near the walk-trot transition. The data also demonstrated that both swing and stance durations could be modified at all speeds, although individual cats may consistently modify one more than the other. Additionally, swing duration appeared to be the primary variable during galloping. These results are discussed in terms of their implications for comparative studies of cat locomotor behavior subsequent to surgically induced lesions, and in terms of achieving a better understanding of cat locomotion and its neural control.

Animals↗
PubMed1996

Behavioural and neurochemical responses of male and female chicks to cat odour.

In the first experiment male chicks were exposed to neutral and cat odours at days 4, 7, or 10 after hatching. Of the chicks tested at day 4, few made contact with either odour cloth, but those tested at day 7 made fewer contacts with the cat odour cloth, compared with the neutral odour, spent less time in contact with it, and spent more time in the zone furthest from the cloth. These clear differences were not seen in the group tested at day 10. In a second experiment, the behaviour of day 7 male chicks was compared in the presence of neutral, disinfectant, chick blood or cat odours, and the most extreme differences were between neutral and cat odours. In a third experiment, both male and female chicks were exposed to cat odour at day 7 and both showed similar avoidance. After exposure to cat odour both sexes showed significantly reduced GABA enhancement of benzodiazepine binding; which is a change associated with increased fear. However, after exposure to cat odour, they also showed significant decreases in 5-HT availability evidenced by lower basal and K(+)-evoked [3H]-5-HT release and, in the male chicks only, by an increased [3H]-5-HT uptake from archistriatal slices. These changes in 5-HT function are in the direction associated with reduced fear and would, therefore, seem to be adaptive and compensatory in function. Neither male nor female chicks showed any differences in [14C]-GABA release or uptake as a result of exposure to cat odour. Although the pattern of response to cat odour was the same in both male and female chicks at day 7, there were significant sex differences in 5-HT and GABA tone and benzodiazepine binding; these sex differences were also found in day 10 chicks. The importance of these for sex differences in trait anxiety is discussed.

Animals↗
PubMed1991

Single-unit recording in the ventral cochlear nucleus of behaving cats.

A method is described for single-unit recording in the ventral cochlear nucleus (VCN) of behaving cats. Five cats were implanted with titanium head-restraint devices and acetal plastic recording chambers. The recording chamber directed microelectrodes through the cerebellum and into the VCN. Electrophysiological recordings were obtained from isolated VCN units while the cats engaged in an auditory discrimination task. The task required the cats to discriminate changes in the temporal pattern of a series of tone or noise bursts. Cats initiated the testing sequence by depressing a lever, and obtained food by releasing the lever when the pattern of stimuli changed from one 200-ms burst/s to four 50-ms bursts/s. Stimulus features (i.e., frequency, level, duration) were manipulated to characterize the physiological responses of VCN units. Preliminary data suggest that peri-stimulus time histograms (PSTHs) and rate-level functions (RALVs) obtained from behaving cats are similar to those previously described in anesthetized and decerebrate cats when units are tested with tones in quiet backgrounds. However, in comparison to anesthetized and decerebrate cats, units obtained in behaving cats demonstrate a more sensitive rate representation of stimulus level when tested in continuous background noise.

Acoustic Stimulation↗
PubMed1982

Electrophysiological and cyclic AMP responses to beta-adrenergic receptor stimulation and catecholamine levels in cat and rabbit sympathetic ganglion.

The effects of beta 1- and beta 2-selective and nonselective adrenergic agonists and antagonists were studied in the cat and rabbit superior cervical ganglion (SCG) in situ and in vitro. In experiments on the cat SCG in situ beta-adrenergic agonists induced an increase in positive afterpotential (PAP) of compound ganglionic action potential evoked by preganglionic stimulation in the following order of potency: isoprenaline (ISO) greater than salbutamol much greater than tazolol. Beta-adrenergic antagonists inhibited the ISO response in the following order of potency: propranolol greater than exaprolol much greater than H 35/25. Practolol did not exhibit beta-adrenergic blocking action; on the contrary, in higher doses it enhanced the response to ISO. In higher doses all beta-adrenergic antagonists tested depressed ganglionic transmission in an approximately similar range of doses. In experiments in vitro, using sucrose-gap technique. ISO induced depolarization of the cat SCG and this effect was inhibited in a dose-dependent manner by propranolol. Beta-adrenergic agonists did not induce depolarization of the rabbit SCG in experiments in situ and in vitro. The level of noradrenaline and dopamine in the cat and rabbit SCG did not differ significantly. Low level of adrenaline was found in the cat SCG; however, no adrenaline was detected in the rabbit SCG. No statistically significant change of cyclic AMP content was observed in the cat and rabbit SCG or in the incubation medium under conditions similar to those in which ISO induced depolarization of the cat SCG. It is concluded that the beta-adrenergic receptors present in the cat SCG resemble the beta 2-subtype and that the presence of an electrophysiologic response to beta-adrenergic agonists appears to be species-dependent. The depolarization of the cat SCG due to beta-adrenergic receptor stimulation is not coupled with cyclic AMP increase.

Action Potentials↗
PubMed1992

Detection of feline immunodeficiency virus infection in bone marrow of cats.

Natural or experimental feline immunodeficiency virus (FIV) infection in cats is often associated with hematologic abnormalities which are similar to those observed in human immunodeficiency virus (HIV) infected patients. To determine if cells in bone marrow are infected with FIV and whether severity of hematopoietic disorder is correlated with the level of viral infection, bone marrow tissues from ten experimentally and two naturally FIV infected cats were examined by in situ hybridization for presence of FIV RNA. Seven of the 12 FIV infected cats were also naturally or experimentally coinfected with feline leukemia virus (FeLV). FIV RNA was detected mainly in megakaryocytes and unidentified mononuclear cells in the bone marrow of cats that were sick and had marrow hypercellularity and immaturity. These included all cats in the acute phase of FIV infection and two of seven long term FIV infected cats. One long term FIV infected cat with lymphosarcoma was also positive for FIV RNA in bone marrow cells. The other four long term FIV infected cats were relatively healthy, with normal bone marrow morphology, and were negative for FIV infected cells. Bone marrow from three non-infected and two cats infected with FeLV alone were also negative for FIV RNA by in situ hybridization. We concluded that megakaryocytes and mononuclear cells were targets of the viral infection and that the presence of FIV RNA in cells of the bone marrow correlated with marrow hypercellularity and immaturity, and severity of illness.

Animals↗
PubMed1985

The organization of cerebellar afferent projections to the paramedian lobule in neonatal cats.

This study sought to determine whether cerebellar afferent pathways, that are topographically organized in adult cats, are similarly ordered during the postnatal development and maturation of the cortex, or whether the projections are first distributed randomly in the cortex before becoming organized. Injections of wheat germ agglutinin-horseradish peroxidase were made into dorsal (dPML) or ventral (vPML) divisions of the paramedian lobule (PML) in neonatal (0- to 21-days-old) and adult cats and the ensuing distributions of retrogradely labeled neurons in the lateral reticular nuclei, the inferior olive and the pontine nuclei were compared. Magnocellular and parvicellular neurons in the dorsomedial and dorsolateral parts of the ipsilateral lateral reticular nuclei project respectively to dPML and vPML in all neonatal and adult cats. Olivocerebellar projections were entirely crossed, in most cases, with neurons projecting to the dPML more rostral and medial in the dorsal and medial accessory nuclei and in the principal olive than neurons which project to the vPML. A parasagittal zonal organization of olivocerebellar projections was present in newborn cats. Neurons were labeled in the ipsilateral inferior olive following dPML injections in 1- to 4-day-old kittens, but not in older kittens or in adult cats. Pontocerebellar projections were bilateral with a contralateral predominance. In adult and neonatal cats, labeled neurons were clustered together and formed rostral-caudal oriented columns dorsomedial and ventromedial to the pyramidal tract after injections in the contralateral dPML and vPML and bilaterally in the dorsolateral pons after dPML injections. These results show that lateral reticulo-, olivo- and pontocerebellar projections to the PML which are topographically organized in adult cats are organized similarly in newborn cats. Studies in prenatal cats are required in order to determine whether these cerebellar afferents are ever randomly distributed in the cerebellar anlage or whether these projections are ordered as they grow into the cerebellum.

Afferent Pathways↗
PubMedDate not supplied

Immediate postoperative retention of visual discriminations following selective cortical lesions in the cat.

Cats were trained preoperatively for brightness discrimination, and 7 pattern and form discriminations, and then retested for preoperative retention on each discrimination. Cortical lesions were then placed in areas 17 and 18 in one group (4 cats), in areas 17, 18 and 19 in another group (3 cats), and in suprasylvian cortex (areas 7, 21, and parts of 19, 5 and the lateral suprasylvian cortex) in a third group (4 cats). Results are also reported for a fourth group with extensive suprasylvian lesions, to which was added an unintended undercutting of areas 17 and 18 (4 cats). While during original preoperative learning the training continued until a fixed, stringent criterion of performance was attained, both preoperative and postoperative retention was tested in short sessions, involving a limited number of trials and a less stringent statistical criterion (significant run). After extensive removal of areas 17 and 18, all cats behaved as though following the cortical lesion they could immediately recognize the discriminative stimuli as efficiently as before, with no need for retraining. On the contrary, the group with areas 17, 18 and 19 lesions showed a substantial postoperative loss of all discriminations, and especially for the more difficult form discriminations, the reattainment of a significant level of performance was hard or impossible within the allotted number of trials. Also in the group with limited suprasylvian lesions, postoperative retention was generally impaired, but the reacquisition of efficient performance was superior to that of the previous group. Finally, large suprasylvian lesions encroaching on the white matter under areas 17, 18 and 19 proved disruptive for all discriminative capacities, both in retention and in relearning. The excellent retention of all discriminations following areas 17 and 18 lesions once again shows that these areas are by no means essential for complex vision in the cat. In addition, the results strongly indicate that the high-level visual capacities of destriate cats are not due to reorganization of readaptation processes occurring in extrastriate areas after a 17/18 removal. The clear-cut retention deficits which were present in cats with cortical lesions more extensive than areas 17 and 18 or outside of the latter areas prove the essential participation of extrastriate cortical areas in visual discrimination including form. However, the distribution of functions among the various visual cortical areas in visual discrimination remains poorly understood.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1996

Vestibular compensation: role of visual motion cues in the recovery of posturo-kinetic functions in the cat.

Vision has long been recognized as a sensorimotor system which plays a major role in substitution for functional deficits induced by unilateral or bilateral exclusion of primary vestibular afferents. Little is known, however, about the post-lesion influence of visual inputs on the recovery of posturo-kinetic balance in a situation where fine, well-coordinated locomotor adjustments are required. The present study was carried out in order to gain some insight into the role played by motion vision in the restoration of fine posturo-kinetic balance in adult cats subjected to unilateral vestibular neurectomy. Prior to the lesion, 15 adult animals were trained to cross a beam rotating at various speeds. Their best global balance performance (highest beam rotation speed that did not provoke falling) and their average locomotion speed were evaluated. After the lesion, the cats were separated into three groups: (1) five animals were placed in a normal environment (animal house) (NV cats); (2) four animals were exposed to stroboscopic illumination which eliminated visual motion cues (SV cats) for 2 weeks following the lesion; and (3) three animals were placed in a normal environment and their training was interrupted for the same period as in the SV cats (NVI cats). The possible influence of the 2-week deprivation of visual motion cues on posturo-kinetic balance was also examined in three intact cats. The present behavioral study showed that: (1) early sensory deprivation caused suspension of the posturo-kinetic balance recovery process as long as it was maintained; (2) complete restoration of global balance capacities developed following the vestibular neurectomy after a significant delay in half of the SV cats; (3) the lack of motion cues resulted in severe alterations of fine posturo-kinetic balance (inappropriate dynamic motor adjustments and irregular locomotion speed regulation) in all SV cats; and (4) the visual deprivation induced a 2-week delay in the restoration of fine locomotor balance. These findings provide evidence for a defect in the visual sensory substitution processes that normally take place within the first few weeks following exclusion of primary vestibular afferents.

Animals↗
PubMed1993

Participation of nucleus entopeduncularis in motor instrumental reflex and entopeduncular influences on motor thalamic nuclei in normal and MPTP-treated cats.

Activity of entopeduncular neurons was studied in chronic experiments on cats during performance of instrumental movement: pedal pressing and holding. One-hundred and twenty-four neurons were extracellularly investigated in intact animals and 81 neurons in cats treated with N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (5 mg/kg daily, intramuscularly for five days). The mean discharge frequency of nucleus entopeduncularis neurons recorded 48-72 h after the last MPTP injection increased from 12.9 +/- 1.5 to 22.1 +/- 1.4 impulses/s, but dropped to preinjection values within the next ten days. In intact animals and in MPTP-treated cats 23 and 17%, respectively, of neurons changed their activity before or during the movement performance. Along with nucleus entopeduncularis neurons that changed their activity simultaneously with instrumental movement performance, 16% of nucleus entopeduncularis nerve cells in intact cats and 12% in MPTP-treated cats responded 50-800 ms before the myogramme of working forepaw biceps was started. Excitatory responses associated with movement performance in MPTP-exposed cats were more pronounced, indicating enhancement of nucleus entopeduncularis neuronal activity in animals with injured nigrostriatal system. Since nucleus entopeduncularis neurons are inhibitory cells, the increase in their activity had to be accompanied by reinforcement of inhibitory influence on neurons in motor thalamic nuclei. In order to test this hypothesis, two groups of acute experiments were performed on ketamine-anaesthetized and myorelaxine-immobilized cats. Neuronal responses in ventral anterior and ventral lateral thalamic nuclei to nucleus entopeduncularis stimulation were investigated in normal and MPTP-treated animals in doses that were identical to those administered in chronic experiments. In intact cats, 28% of neurons responded to nucleus entopeduncularis stimulation with the latency shorter than 7 ms. In half of the inhibited neurons after the first phase of inhibition lasting 18 +/- 2 ms, the second inhibitory phase was recorded. The duration of the latter was 24 +/- 4 ms. Although in MPTP-treated cats the number of neurons inhibited by nucleus entopeduncularis stimulation was practically the same as in normal ones (24.5%), the first phase tended to be shorter, and a statistically significant increase of the second inhibitory phase duration (up to 50 +/- 11 ms) was found. It was suggested that changes in the inhibitory processes in motor thalamic neurons receiving afferents from nucleus entopeduncularis could be explained by GABAB-mediated hyperpolarization of the neuronal membrane, evoked by increasing pallidothalamic inhibitory influences.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2004

Effect of dorsal periaqueductal gray lesions on cardiovascular and behavioral responses to cat odor exposure in rats.

Previously we demonstrated Fos expression in the dorsal periaqueductal gray (DPAG) of the rat following cat odor exposure. Further work correlated the response to cat odor with a sustained blood pressure increase and deployment of defense behavior. It was therefore of interest to determine whether lesions of the DPAG would abolish these two effects of cat odor exposure. Male Wistar rats were given excitotoxic NMDA (N-methyl-D-aspartate) lesions of the DPAG and anterior tectum under halothane, then implanted with blood pressure telemetric probes. Sham lesions were made with saline. Rats were then exposed to cat odor with a hide option, followed 2 weeks later by re-exposure to cat odor without a hide option. Controls were exposed to rat odor in the same way. Trends toward attenuation in defense and cardiovascular indices were found in lesioned rats for cat odor exposure with a hide option, but these were not significant. Re-exposure to cat fur without a hide option enhanced the cardiovascular response and under these conditions, lesioned rats showed a significant change of the heart rate and locomotor activity response to cat fur. However, the blood pressure response was not significantly attenuated. Thus, the present results support the Fos data and indicate that the DPAG is involved in the expression of some but not all of the cardiovascular and behavioral components of the response to cat odor.

Animals↗
PubMed2005

Cloning and pharmacological characterization of the cat urotensin-II receptor (UT).

Urotensin-II (U-II), acting through its G-protein-coupled receptor, UT, is a possible contributor to hypertension. Variable functional responses to U-II, both within and between species studied to date, complicate the characterization of UT antagonists. In the cat, however, U-II causes systemic hypertension and constricts arterial segments isolated from several vascular beds. The purpose of this study was to clone and pharmacologically characterize cat recombinant UT to determine whether this system represents a model for characterizing UT antagonists. Cloned cat UT displayed 74% identity to primate UT, and 77% identity to rodent UT. [(125)I] hU-II bound in a saturable manner to a single site on recombinant cat UT with high affinity (K(D) 288+/-13pM) and high density (B(max) 747+/-66fmol/mg protein). U-II isopeptides displayed equipotent, high affinity binding to cat UT (K(i) 1.8-5.3nM). Cat UT was coupled to intracellular [Ca(2+)] release (EC(50) 0.6+/-0.2nM) and total inositol phosphate (IP) formation (EC(50) 0.4+/-0.1nM). Protein kinase C activation desensitized cat, but not human, UT-mediated IP formation. UT mRNA expression was detected in cat blood vessels, trachea, lung, and kidney, where the medulla (K(D) 815+/-34) and cortex and (K(D) 316+/-39pM) displayed high affinity binding for human U-II (hU-II). The cat urotensin-II receptor represents a suitable in vitro model to examine the role of the U-II/UT system in the etiology of hypertension, assisting in the evaluation of the UT antagonists to help treat cardiovascular disease.

Amino Acid Sequence↗
PubMed2004

Presence and timing of cat ownership by age 18 and the effect on atopy and asthma at age 28.

BACKGROUND: Asthma and allergic sensitization to cats frequently coexist, although recent studies show less atopic disease among people who had pets in infancy. However, no longterm evaluations have been performed thus far. OBJECTIVE: We sought to evaluate the relationship between cat ownership at different age periods (< 18, > 18, and both periods and atopic disease at age 28. METHODS: Australian school children aged 8 to 10 years were recruited in 1982 and participated in follow-up surveys until 2002. Cat ownership was defined by surveys in 1992 and 2002 as having a cat before age 18 only, after age 18 only, or in both periods of life. Health outcomes were defined at a mean age of 28.5 years. RESULTS: Complete data were available for 224 subjects, 50 of whom had a cat before 18 years of age only, 14 after age 18 only, and 70 in both periods. Compared with 90 subjects that never had a cat, having a cat before age 18 protected against atopy to outdoor allergens, airway hyperresponsiveness (AHR) to histamine, current wheeze, and current asthma (P < .05). In contrast, subjects who acquired their first cat after age 18 showed a trend toward higher prevalence rates for asthma symptoms and AHR (P > .10). CONCLUSIONS: Having had a cat before 18 years of age protects against adult asthma and atopy.

Adolescent↗
PubMed2004

Dose dependence and time course of the immunologic response to administration of standardized cat allergen extract.

BACKGROUND: The immunologic response to allergen immunotherapy with 3 serial 5-fold doses of cat extract has been studied after approximately 5 weeks of immunotherapy. The highest dose containing 15 mug of Fel d 1 produced the most consistent and favorable response. It is unknown whether the comparative response on reaching a maintenance dose is maintained with long-term maintenance therapy. OBJECTIVE: The purpose of this investigation was to evaluate the immunologic responses with these 3 serial doses of cat hair and dander extract at baseline, after reaching the maintenance dose (approximately 5 weeks), and after 1 year of maintenance immunotherapy. METHODS: Twenty-eight patients with cat allergy randomized in a double-blind study were assigned to one of 4 treatment groups: placebo or cat hair and dander extract containing 0.6 mug of Fel d 1, 3 mug of Fel d 1, and 15 mug of Fel d 1 at maintenance. Studies included skin prick tests and late cutaneous reactions with cat hair and dander extract, titrated nasal challenges with the extract, serum cat allergen-specific IgG4 and IgE measurement, and flow cytometric and ELISA analysis of whole blood and intranasal cytokines (TGF-beta, IL-10, IFN-gamma, IL-4, and IL-5). RESULTS: Twenty-six subjects completed the study. After both 5 weeks and 1 year, significant and dose-dependent differences were seen with total symptom scores on nasal challenge ( P < .0001), with titrated skin prick testing with cat dander extract at 5 weeks ( P = .014) and 1 year ( P < .0001), and with cat-specific IgG4 measurement at 5 weeks ( P = .004) and 1 year ( P = .003). At 1 year, neither flow cytometry of whole blood nor ELISA evaluation of nasal cytokines demonstrated any significant differences among the treatment groups. CONCLUSION: The response to titrated nasal allergen challenge, titrated skin prick testing, and allergen-specific IgG4 measurement to cat immunotherapy at 5 weeks is predictive of the response at 1 year.

Allergens↗
PubMed2006

Developmental pattern of M1 and M2 muscarinic gene expression and receptor levels in cat carotid body, petrosal and superior cervical ganglion.

Using real-time reverse transcriptase polymerase chain reaction, Northern blot, and Western blot analyses, we evaluated the developmental pattern of mRNA and protein expression level of muscarinic M1 and M2 receptors in the carotid body, petrosal ganglion and superior cervical ganglion of 1-day, 15-day, 2-month-old and adult cats. mRNA expression and protein levels of tyrosine hydroxylase, the rate limiting enzyme for dopamine synthesis, were also assessed. Carotid body M1 receptor mRNA, increased significantly by approximately 100% and 300% in 2-month and adult vs. 1- and 15-day-old cats, but protein level decreased gradually being approximately 50% lower compared with 1-day-old cats. In the petrosal ganglion, muscarinic M1 receptor mRNA level was higher in 15-day-old cats vs. 1-day-old, 2-month-old and adult cats and protein levels were about 30% lower than in 1- and 15-day-old cats. In the superior cervical ganglion, muscarinic M1 receptor mRNA was approximately 50% and 80% higher in 2-month-old and adult cats than 1- and 15-day-old, but no changes in the protein level except in 15-day-old cats which was approximately 40% higher than 1-day-old. There was no change of muscarinic M2 receptor mRNA or protein level in the carotid body or petrosal ganglion. However, in the superior cervical ganglion, the significant increase of mRNA of 30% and 50% in 2-month-olds and adults, respectively was not associated with an increase in receptor protein. Tyrosine hydroxylase mRNA and protein level decreased significantly with age in the carotid body and petrosal ganglion. In the superior cervical ganglion, the age dependent increase in tyrosine hydroxylase mRNA was not associated with any changes in the protein level. These results show that the expression of muscarinic M1 and M2 receptors are age and organ-dependent in cats. Consequently, these changes may modulate chemosensory activity during development since muscarinic M1 receptor is predominantly involved in postsynaptic chemosensory activity, while muscarinic M2 receptor modulates acetylcholine and dopamine release from chemosensitive cells.

Age Factors↗
PubMed2005

Survey of zona pellucida antigens for immunocontraception of cats.

The purpose of this study was to screen a panel of native zona pellucida (ZP) antigens isolated from five mammalian species for immunocontraceptive activity in the cat (Felis catus). Native soluble-isolated ZP (SIZP) was prepared from the ovaries of cows (bZP), cats (fZP), ferrets (feZP), dogs (cZP), and mink (mZP). Vaccines were constructed using SIZP from each of the above species encapsulated in liposomes suspended in saline and emulsified with Freund's complete adjuvant (SpayVac). Female cats were immunized once (n = 3 cats per group). Serum was collected for determination of antibody titers against SIZP and for binding of antibodies to feline ovaries. All cats responded to immunization by producing anti-SIZP antibodies. The most immunogenic SIZP in cats was from mink, followed by feZP, cZP, and fZP in descending order. Antibodies had low reactivity for fZP, and no reactivity against feline ovaries was detected by immunohistochemistry. A breeding trial was commenced 20 weeks after immunization. All cats became pregnant, averaging 4.1 +/- 0.7 viable kittens per litter. We have previously shown that porcine SIZP is not an effective antigen for immunocontraception of cats. In this study, SIZP from five other mammalian species were immunogenic in the cat, but ZP antibodies failed to bind to fZP in situ, and fertility was not impeded.

Animals↗
PubMed2004

Assessment of CD4+ and CD8+ IFN-gamma producing cells by ELISPOT in naïve and FIV-infected cats.

IFN-gamma is critical for the development of antiviral cell-mediated immunity in HIV infected humans and FIV infected cats. The ELISPOT has proven to be a technically straightforward assay to quantify the number of IFN-gamma producing cells and offers a reasonable alternative for the quantitative measurement of T-cell function in cats. We used a feline-specific ELISPOT to identify constitutive as well as Con A stimulated IFN-gamma production in T-cell subsets and determine if there were differences between purified (positively sorted) and negatively depleted populations from naïve and FIV infected cats. We found no difference in the total number of PBMC constitutively producing IFN-gamma in naïve and FIV+ cats. Con A exposure was associated with increased numbers of IFN-gamma producing PBMC in naïve, but not FIV+, cats. Equivalent numbers of CD4+ and CD8+ T cells constitutively expressed IFN-gamma in naïve cats. However, in FIV+ cats, the number of IFN-gamma producing CD8+ T-cells was approximately two-fold over that seen for CD4+ T-cells. We found minimal differences between purified (e.g. CD4+ or CD8+) and corresponding depleted (e.g. CD8- or CD4-) populations in samples from FIV+ cats. In contrast, depleted populations from naïve cats showed greater response to Con A than did purified populations. Thus, while determination of the number of IFN-gamma producing cells by feline-specific ELISPOT is a useful tool for the evaluation of the feline immune response, determination of the initial sample population and T-cell subset is critical for optimal interpretation of the IFN-gamma ELISPOT.

Animals↗
PubMed1989

Rhodopsin levels and rod-mediated function in Abyssinian cats with hereditary retinal degeneration.

Abyssinian cats with different stages of a slowly progressive autosomal recessively-inherited retinal degeneration were studied with imaging fundus reflectometry (IFR) and electroretinography (ERG). Maps of the visual pigment distribution were made in an area of retina extending from the posterior pole to the midperiphery. Rhodopsin levels in the midperipheral retina of a 6-month-old affected cat (stage of suspected disease) were reduced about 20% relative to the mean normal value. The same cat, tested at 2.5 yr of age (now moderately advanced stage), showed a 60% reduction. A 3-yr-old affected cat (also moderately advanced) had a reduction in rhodopsin of about 60%. There was no measurable rhodopsin in a 7-yr-old affected cat (advanced stage). Rhodopsin regeneration kinetics at the different stages of disease were found to be similar to those of normal cats. The rod ERG b-wave threshold in the 6-month-old cat was elevated by 0.26 log units; at 2.5 yr of age, the threshold was elevated by 0.48 log units. A 0.34 log units threshold elevation was found in the 3-yr-old cat. There was no detectable ERG in the 7-yr-old cat. The relationship between the rod ERG threshold elevations and the rhodopsin levels was close to that expected if the dysfunction was caused by decreased quantal absorption.

Animals↗