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[Adenomatoid tumor of the testes--a rare entity. Clinical, diagnostic and therapeutic aspects].

Adenomatoid tumor with intra-testicular localization is rare. Although most reported cases arise from the epididymis, rare cases have been reported in the testicular tunica, spermatic cord, ejaculatory ducts, prostate and suprarenal recess. Adenomatoid tumors occur in both sexes and are also found in the uterus, ovary and fallopian tubes of the female genital tract. Adenomatoid tumors are benign proliferations of mesothelial origin. We report the case of a 50-year-old male with an adenomatoid tumor of the left testis. Because of its rarity, the clinical, diagnostic and therapeutic aspects as well as the possibilities of testicular preservation are discussed.

Adenomatoid Tumor↗

Otolith organ or semicircular canal stimulation induces c-fos expression in unipolar brush cells and granule cells of cat and squirrel monkey.

Immediate early gene expression in the cerebellar vermis of cats and squirrel monkeys was stimulated by prolonged whole body rotations. Continuous, earth-horizontal axis rotations that excited only otoliths or high velocity vertical axis rotations that excited only semicircular canals resulted in c-fos immunoreactive nuclei concentrated in the granular layer of lobules X and ventral IX (the nodulus and ventral uvula), which represent the medial parts of the vestibulo-cerebellum. Large clusters of labeled nuclei consisting mainly of granule cells and calretinin-positive unipolar brush cells were present in the granular layer, whereas Purkinje cell nuclei were unlabeled, and labeled basket and stellate cell nuclei were scattered in the molecular layer. In other vermal lobules there was a significant but less dense label than in the nodulus and ventral uvula. Generally, the extent of c-fos labeling of molecular layer interneurons was in relation to nuclear labeling of granular layer neurons: labeling of both basket and stellate cells accompanied nuclear labeling of neurons throughout the depth of the granular layer, whereas only stellate cells were labeled when nuclear labeling was restricted to the superficial granular layer. Yaw horizontal or roll vertical rotations each stimulated c-fos expression in the cat medial vestibulo-cerebellum to approximately the same extent. Low-velocity rotations resulted in much less c-fos expression. Similar, albeit less intense, patterns of c-fos activation were observed in monkeys. Concentrated c-fos expression in the medial vestibulo-cerebellum after exposure to a strong head velocity signal that could originate from either otolith or canal excitation suggests that granule and unipolar brush cells participate in a neuronal network for estimating head velocity, irrespective of the signal source.

Animals↗

Abnormal vestibular control of gaze and posture in a strain of a waltzing rat.

The waltzing behavior is usually attributed to vestibular dysfunction. However, the vestibular control of gaze and posture has not yet been measured quantitatively in any waltzing mutant. Therefore, this study was aimed at investigating the relationship between inner-ear morphology, the circling behavior, and the vestibular control of gaze and posture in a new strain of waltzing rats. Light- and electron-microscopy studies of these mutants did not reveal any structural abnormalities of the vestibular neural epithelia. In addition, the expression of Calretinin and 200-kD phosphorylated and non-phosphorylated neurofilaments was also found to be normal in the vestibular neural epithelia and ganglion cells. In contrast, the mutants showed severe dysfunctions of the vestibular control of gaze and posture. The skeletal geometry of the alert unrestrained animals was studied using cineradiography. At rest, waltzing rats held their heads tilted down: the horizontal semicircular-canal's plane was near the earth-horizontal's plane, instead of being tilted up as in Long Evans control rats. In addition, their cervical column was pitched more forward (33.6 degrees) than in the control group (6.9 degrees). The circling behavior was observed frequently, and the rats had episodes of circling in both directions. The episodes of circling amounted to an average of 17 turns, and the average angular velocity of the circling was 645 degrees/s. Unilateral labyrinthectomy induced the same postural and oculomotor syndromes in the waltzing and control groups. This indicates that the mutant vestibular nerve had a significant resting discharge before the lesion. Eye movements were recorded using acutely implanted search coils. Although waltzing rats were able to perform normal spontaneous eye movements, they showed a complete deficit of the horizontal vestibulo-ocular reflex (HVOR) and an impairment of the maculo-ocular reflex (MOR) during constant velocity, off-vertical axis rotation (OVAR). These results show, for the first time, that deficient transduction and/or processing of the horizontal-canal- and macular-related information can be causally related to the circling behavior and abnormal posture, respectively.

Animals↗

Estrogen receptor-alpha in the raphe serotonergic and supramammillary area calretinin-containing neurons of the female rat.

It is well established that estrogen affects hippocampal long-term potentiation and hippocampus-related memory processes. Furthermore, theta rhythm, in conjunction with long-term potentiation, influences memory and is regulated by subcortical structures, including the median raphe and supramammillary area. To test the validity of the hypothesis that the effects of estrogen on the hippocampus are mediated, at least partly, via these subcortical structures, it must first be determined whether the neurons of the median raphe and supramammillary area contain estrogen receptors. Light and electron microscopic double immunostaining for estrogen receptor-alpha plus serotonin and estrogen receptor-alpha plus calretinin on vibratome sections of the median raphe and supramammillary area, respectively, demonstrated that large populations of the median raphe serotonin and supramammillary area calretinin neurons exhibit estrogen receptor-immunoreactive nuclei. These observations indicate that circulating gonadal hormones can affect hippocampal electric activity indirectly, via those subcortical structures that are involved in theta rhythm regulation.

Animals↗

Cerebral lipoma and the underlying cortex of the temporal lobe: pathological features associated with the malformation.

Intracranial lipomas are believed to be congenital malformations rather than true neoplasms, resulting from the abnormal differentiation of the meninx primitiva, the undifferentiated mesenchyme. We report here the surgical pathological features of a lipoma that was located on the cerebral surface of an abnormally formed fissure, and the underlying cortex of the middle temporal gyrus of a 20-year-old woman. The mass was composed of typical adipose tissue in which a large number of blood vessels were present. Thick connective tissue associated with the arachnoid membrane covered the cortical surface. The cortex exhibited a polymicrogyric configuration in which the cortical ribbon was abnormally undulated and excessively folded. Reelin-immunolabeled Cajal-Retzius-cell-like cells were observed frequently in the fused molecular layer. The cortical lamination underlying the molecular layer was poorly defined. Along the border between the connective tissue and cortical surface, there was a narrow zone in which the mesenchymal and neuronal tissues were intermingled, and where immunohistochemical and ultrastructural investigations disclosed disruption of the basal lamina, prominent astrocytosis, and abundant axonal and synaptic profiles. These findings suggest that focal disturbances in cerebral cortical development occur in association with the development of lipomas.

Adult↗

An increase of hippocampal calretinin-immunoreactive neurons correlates with early febrile seizures in temporal lobe epilepsy.

Numerous studies indicate that initial precipitating injuries (IPI) such as febrile seizures during early childhood may play a pivotal role in the pathogenesis of temporal lobe epilepsy (TLE) and Ammon's horn sclerosis (AHS). Previous data demonstrate an increase of horizontally oriented neurons in molecular layers of hippocampal subfields, which are immunoreactive for calretinin (CR-ir) and resemble Cajal-Retzius-like cells. Cajal-Retzius cells are transiently expressed in the murine developing hippocampus and are critically involved in neuronal pattern formation. Here we investigated a potential relationship between the distribution of horizontally oriented calretinin-immunoreactive neurons and the clinical history of TLE patients with AHS. Horizontally oriented neurons in the molecular layer of the hippocampal formation have been visualized by antibodies against the calcium-binding proteins calretinin and calbindin D-28k. Cell counts derived from 27 epilepsy patients with AHS were compared with autopsy specimens from developing and adult normal human hippocampus (n = 26). During ontogeny, CR-ir cells showed a marked perinatal peak in the CA1 and dentate gyrus molecular layer (CA1-ML, DG-ML) followed by a gradual postnatal decline. In hippocampal specimens from TLE patients with AHS and seizure onset before the age of 4 years, significantly higher levels of CR-ir neurons in CA1-ML (P = 0.05) and DG-ML (P < 0.05) were encountered than in AHS patients without precipitating seizures or with an uneventful early medical history. However, all three groups had higher levels of CR-ir neurons compared to adult controls obtained at autopsy (P < 0.01). In addition, AHS specimens showed increased CR-ir neuropil staining throughout the DG-ML compared with the restricted distribution of CR-ir fibers within the superficial granule cell layer visible in controls. These findings suggest that a considerable number of TLE patients with AHS display signs of impaired hippocampal maturation and circuitry formation as indicated by increased numbers of Cajal-Retzius like cells. It remains to be elucidated, how these changes contribute to the pathogenesis of TLE.

Adolescent↗

Recombined DNA vaccines encoding calreticulin linked to HPV6bE7 enhance immune response and inhibit angiogenic activity in B16 melanoma mouse model expressing HPV 6bE7 antigen.

Calreticulin (CRT) has been reported to have an effect of upregulating MHC class I presentation as well as inhibiting angiogenesis in vitro and in vivo. Combination of dual mechanisms of enhanced immunogenicity of human papillomavirus (HPV) 6bE7 antigen and antiangiogenesis may be introduced in the strategy of vaccines against condyloma acuminatum (CA) resulting from HPV infection. Therefore, we constructed DNA vaccines by employing different lengths of CRT chimerically linked to a model antigen HPV6bE7 and investigated the immunological and antiangiogenic effects of these vaccines in a B16 melanoma model that express HPV6bE7 antigen. Our results showed that vaccination with CRT180/HPV6bE7 or CRT120/HPV6bE7 enhanced the presence of CD8(+) T cells and TCRgammadelta T cells in vivo, increased the specific lysis activity against E7-expressing cells and secretion levels of IL-2 and IFN-gamma by activating T cells in vitro significantly. Moreover, recombined CRT180 or CRT120 with HPV6bE7 vaccines could elicit a more efficient E7-specific immune response than HPV6bE7 alone. The similarity of immunological enhancement of CRT180/HPV6bE7 and CRT120/HPV6bE7 implies that the immunologically active region mainly exist in fragment 1-120 aa. Furthermore, CRT180/HPV6bE7 and CRT180 displayed remarkable superiority over CRT120/HPV6bE7 in vivo angiogenesis assay, suggesting that the antiangiogenic activity of CRT resides in a domain between aa 120 and 180. Vaccination with CRT180/HPV6bE7 generated the best protective effect of delaying tumor formation and reduction of tumor size in tumor growth inhibition experiment among all DNA constructs. Therefore, CRT180/HPV6bE7 vaccine may enhance the immunological response to HPV6bE7 and inhibit angiogenesis. This construct may be useful in preventing HPV-associated dermatosis and may be developed as a promising strategy to control CA.

Animals↗

Distribution of P2Y2 receptors in the guinea pig enteric nervous system and its coexistence with P2X2 and P2X3 receptors, neuropeptide Y, nitric oxide synthase and calretinin.

The distribution of P2Y2 receptor-immunoreactive (ir) neurons and fibers and coexistence of P2Y2 with P2X2 and P2X3 receptors, neuropeptide Y (NPY), calretinin (CR), calbindin (CB) and nitric oxide synthase (NOS) was investigated with immunostaining methods. The results showed that P2Y2-ir neurons and fibers were distributed widely in myenteric and submucous plexuses of the guinea pig stomach corpus, jejunum, ileum and colon. The typical morphology of P2Y2-ir neurons was a long process with strong positive staining on the same side of the cell body. The P2Y2-ir neurons could be Dogiel type 1. About 40-60% P2X3-ir neurons were immunoreactive for P2Y2 in the myenteric plexus and all the P2X3-ir neurons expressed the P2Y2 receptor in the submucosal plexus; almost all the NPY-ir neurons and the majority of CR-ir neurons were also immunoreactive for P2Y2, especially in the myenteric plexus of the small intestine; no P2Y2-ir neurons were immunoreactive for P2X2 receptors, CB and NOS. It is shown for the first time that S type/Dogiel type 1 neurons with fast P2X and slow P2Y receptor-mediated depolarizations could be those neurons expressing both P2Y2-ir and P2X3-ir and that they are widely distributed in myenteric and submucosal plexuses of guinea pig gut.

Animals↗

Rodent pancreatic islet cells contain the calcium-binding proteins calcineurin and calretinin.

Calcium is known to be of critical importance for hormone secretion in the insulin-producing B-cells of the endocrine, pancreas. Calcium-mediated intracellular signal transduction and the regulation of the concentration of free calcium in B-cells probably involve calcium-binding proteins. In the present study, we have investigated the expression of the calcium/calmodulin-dependent phosphatase, calcineurin, and the EF-hand calcium-binding protein, calretinin, in pancreata of hamsters, gerbils, and rats by immunocytochemistry. Immunocytochemical investigations of serial semithin sections of plastic-embedded pancreata revealed that calcineurin and calretinin were constantly present in islet cells of all three species. In addition to B-cells, these proteins could also be detected in glucagon (A-), somatostatin (D-), and pancreatic polypeptide (PP-) cells. Non-B-cells, especially glucagon-producing A-cells, often exhibited a significantly higher degree of immunoreactivity for both calcium-binding proteins than B-cells. Thus, calcineurin and calretinin may play distinct roles in the regulation of calcium-dependent secretory activities of the different pancreatic endocrine cell types.

Animals↗

Selective immunocytochemical localisation of calretinin in the human ovary.

Calretinin is a calcium-binding protein which is primarily expressed by certain cells of the nervous system, both central and peripheral. Its presence in nonexcitable cells has been little studied. Using a polyclonal antibody and paraffin sections we have analysed the presence of calretinin in the human ovary of different ages, and in polycystic ovaries. Our results revealed the selective presence of calretinin, specifically localised in the cells of the germinal epithelium, those of the theca interna and the theca lutein cells, in the cells of the neurovaso-epithelial association and of the canalicular structures of the mesovarium. Calretinin was also present in a few cells of the theca externa and some interstitial cells. No appreciable quantitative differences in the strength of the positive reaction were seen between the ovaries of different ages or between the normal and the polycystic ovaries. The presence of calretinin was confirmed by western blot analysis. The selective presence of calretinin in the human ovary, in androgenic cells and in the cells of the germinal epithelium is discussed in relation to its possible function as a Ca2+ buffer.

Adult↗

Projections and neurochemical coding of motor neurones to the circular and longitudinal muscle of the guinea pig gastric corpus.

The present study identified projection and neurochemical coding patterns of intrinsic circular (CMN) and longitudinal muscle motor neurones (LMN) in the guinea pig stomach by using the retrograde tracer DiI (1,1'-didodecyl-3,3,3',3'-tetramethylindocarbocya-nine perchlorate) in combination with the immunohistochemical demonstration of choline acetyltransferase (ChAT), enkephalin (ENK), neuropeptide Y (NPY), nitric oxide synthase (NOS) and substance P (SP). Populations of LMN and CMN had similar neurochemical coding and a clear polarity of projection. Taking all DiI-labeled cell bodies as 100%, ascending pathways exhibited the coding ChAT/- (CMN:14.7%/LMN: 18.3%), ChAT/ENK (15.7%/10.1%), ChAT/SP/+/-ENK (19.2%/16.4%), or ChAT/NPY (4.4%/7.6%); descending pathways had the coding NOS/- (13.8%/16.9%), NOS/NPY (9.9%/17%), NOS/ENK (4.4%/1.2%) or NOS/NPY/ENK (13.0%/5.5%). The relative contributions of these populations were not different between CMN and LMN. However, target-specific projection patterns were revealed: most LMN (82%) had longitudinal whereas most CMN (58%) had circumferential projection preferences. The results indicate that gastric circular and longitudinal muscle layers are innervated by ascending excitatory and descending inhibitory pathways in the myenteric plexus. The projection patterns of CMN and LMN were different and followed the orientation of the muscle layers. It is suggested that the specific muscle motor pathways in the gastric myenteric plexus coordinate the reflex-mediated phasic and tonic activity of gastric muscle layers.

Animals↗

Spindle cell tumours of the pleura: a clinical, histological and comparative genomic hybridization analysis of 14 cases.

We examined 14 spindle cell tumours of the pleura that were sent to a Mesothelioma Panel for re-evaluation after a primary suspicion of mesothelioma. The clinical, histological, immunohistochemical and CGH findings were investigated. Final diagnoses were eight sarcomatoid mesotheliomas (SM) and six non-mesotheliomas: two pulmonary sarcomatoid carcinomas, an epithelioid hemangioendothelioma, a malignant solitary fibrous tumour, a malignant pleural smooth muscle tumour and an extraskeletal osteosarcoma. Seven of the eight SM and two of the other six tumours presented with unilateral pleural effusion, dyspnoea, and chest pain, which are characteristic clinical findings in malignant mesothelioma. No single antibody used in the immunohistochemistry separated SM from other tumour types. The most frequently observed chromosomal losses in SM were 4q, 4p11-p13/p15, 6q and 13. Losses of 4p11-p13/p15 and 4q occurred in combination in four out of five SM with detectable chromosomal changes, but neither was found in any of the other tumours. Gain or high-level amplification of 5p was also common in SM. According to our results and literature, losses at 4p, 4q and 9p and gain at 5p are the chromosomal changes that best differentiate SM from pleural sarcomas and lung carcinomas. CGH analysis may help distinguish a cytokeratin-positive SM from a sarcomatoid carcinoma. Similarly, in the case of a cytokeratin-negative tumour, CGH analysis may disclose chromosomal changes characteristic of sarcomas or mesotheliomas.

Aged↗

Calretinin immunoreactivity in the prenatally developing olfactory systems of the tree shrew Tupaia belangeri.

The prenatal patterns of calretinin immunoreactivity were studied in the olfactory systems of Tupaia belangeri. We investigated the peripheral and primary central parts of the vomeronasal system and of the main olfactory system from the 19th to the 43rd (last) day of gestation and compared the findings with the known calretinin immunoreactivity patterns in adult T. belangeri and the published data on other mammals. The onset of calretinin immunoreactivity was noted in the main olfactory system on the 23rd day of gestation and, in the vomeronasal system, on the 25th day of gestation: single precursors of receptor cells with calretinin immunoreactive perikarya and processes were observed in both epithelia. Their neuronal identity was proven by olfactory marker protein immunoreactivity. On the 42nd day of gestation, almost all receptor cells and nerve fibers, many interneurons and projecting cells were calretinin immunoreactive in the main olfactory and in the vomeronasal systems. In contrast to the intensive calretinin labeling previously observed in virtually all vomeronasal epithelial cells of adult T. belangeri, among developing receptor cells a population of intensively labeled, basally located perikarya was distinguishable from a population of less intensively stained, more apically located ones. In the main olfactory epithelium of fetal T. belangeri, calretinin immunoreactive receptor cells occurred in the middle layers. Whereas in the vomeronasal sensory epithelium differently reacting layers of receptor cells might represent the two known subfamilies of receptor cells, in the main olfactory epithelium the differing calretinin expression in the layers of the epithelium, most probably, did not reflect known subfamilies of odour receptor cells. Transiently, ectopic calretinin immunoreactive receptor cells were observed in the future non-sensory epithelium of the vomeronasal organ.

Age Factors↗

Intraganglionic laminar endings in the rat esophagus contain purinergic P2X2 and P2X3 receptor immunoreactivity.

Intraganglionic laminar endings (IGLEs) represent the most prominent vagal afferent terminal structures throughout the gastrointestinal tract. They are most prominent in the esophagus and stomach, but can be found down to the distal colon. Their role as mechanosensors as proposed on anatomical grounds was recently substantiated in elegant functional experiments. There is evidence that vagal mechanosensors in the esophagus and stomach respond to ATP. Thus, the present study aimed at detecting purinergic receptors on IGLEs. IGLEs in the rat esophagus were identified by immunohistochemistry for calretinin and sections were co-incubated with antibodies directed against P2X2 or P2X3 receptors. Also, double label immunocytochemistry for purinergic receptors and calcitonin gene-related peptide as a marker for spinal afferents was performed. Terminal nerve fibers immunoreactive for P2X2 and P2X3, respectively, were observed between outer and inner layers of the tunica muscularis, covering myenteric ganglia totally or partly. Both P2X2 and P2X3 receptor immunoreactivities were highly co-localized with calretinin positive IGLEs as shown by confocal laser scanning microscopy. Numerous calcitonin gene-related peptide immunostained fibers were found to closely approach and intermingle with P2X immunopositive IGLEs. However, there was never co-staining for either of the purinergic receptors and calcitonin gene-related peptide within the same fibers. P2X3 but not P2X2 immunoreactivity was also observed within nerve fiber arborizations in the mucosa of the pharynx. In the nodose ganglion, 8.9 +/- 1.1% of P2X2 and 7.2 +/- 1.3% of P2X3 immunopositive neurons, respectively, co-stained for calretinin. On the other hand, 63.4 +/- 4.6% and 60.1 +/- 5.3% of calretinin positive cell bodies contained P2X2 and P2X3 receptor immunoreactivity, respectively. These results indicate that IGLEs are equipped with both P2X2 and P2X3 receptors. Thus, they may act as chemosensors or their mechanosensory properties may be modulated by ATP. It is also suggested that spinal afferents innervating the esophagus are equipped with neither P2X2 nor P2X3 purinergic receptors.

Animals↗

Development of the amygdalohypothalamic projection in the mouse embryonic forebrain.

The amygdalohypothalamic projection, a major component of the stria terminalis, is involved in the conduction of emotional and olfactory information integrated in the amygdala to the hypothalamus to elicit emotional reactions. Despite the extensive studies on functional aspects of the amygdaloid complex, developmental mechanisms of the amygdala and related structures are still poorly understood. To investigate the development of the amygdalohypothalamic projection in the mouse embryonic brain, carbocyanine dye was applied to the amygdala to label the growing axons anterogradely and to the hypothalamus to label the amygdaloid neurons retrogradely. The initial outgrowth of the stria terminalis was found to be as early as E11.5. The pathway crossed in a saddle over the internal capsule, another prominent connection in the developing forebrain of the mammalian embryo. Bipolar immature neurons were distributed along the stria terminalis at the telencephalo-diencephalic boundary, and the internal capsule was also surrounded by these cells. These cells expressed immunoreactivities to calretinin and the lot-1 antigen which has been shown to be involved in guidance of the developing lateral olfactory tract. Ultrastructural analysis revealed an adherens-like junction between the stria terminalis and the apposed cells, implying contact-mediated guidance. These results suggest that, in the development of the stria terminalis, the axonal outgrowth is guided by a mechanism similar to that of the developing lateral olfactory tract, a major amygdalopetal connection.

Adherens Junctions↗

Enrichment of unipolar brush cell-like neurons in primary rat cerebellar cultures.

Unipolar brush cells are a distinct class of excitatory interneurons situated in the granular layer of the cerebellar cortex, where they form giant synapses with individual mossy fiber terminals. We have previously shown that primary cerebellar cell cultures from embryonic and postnatal rodents contain neurons displaying morphological and chemical phenotypes characteristic of unipolar brush cells in situ, including intense staining with calretinin antiserum. In cultures from both embryonic and postnatal rats, the large majority of calretinin-positive neurons are unipolar brush cells, while granule cells are usually calretinin-negative. A small percentage of putative Golgi/Lugaro cells also express calretinin. We demonstrate here that the developmental stage of the source tissue, the concentration of potassium in the medium, and treatment with glutamate after differentiation have substantial effects on the density of putative unipolar brush cells in the cultures. In dissociated cultures obtained from embryos at gestation day E18 and E20 and from pups at postnatal day P0, P2, P5, P8, and P10 grown in 25 mM KCl, the percentage calretinin-positive cells progressively decreases from 24% to 0.1% of total cells. In cultures from E20 embryos grown in physiological potassium (5 mM KCl), calretinin-positive cells are enriched to approximately 60% of total cells, while the majority of calretinin-negative cells die. In embryonic cultures exposed to high concentrations of glutamate after 12 days in vitro, calretinin-positive neurons have a survival advantage over calretinin-negative cells and represent up to 83% of total cells.

Animals↗

Chemical coding of neurons in the myenteric plexus and external muscle of the small and large intestine of the mouse.

Immunohistochemical techniques were used to examine the presence and co-localisation of a range of putative neurotransmitters and other neuronal markers in the myenteric plexus of the small and large intestine of the mouse. Distinct sub-populations of myenteric neurons were identified, based on the combinations of substances they contained and the distribution of their fibres. In the small intestine, there were two major classes of circular muscle motor neurons; one class was characterised by the presence of nitric oxide synthase, vasoactive intestinal peptide plus neuropeptide Y (NOS/VIP/NPY), and the second class contained calretinin plus substance P (CalR/SP). There were seven classes of neurons that innervated myenteric ganglia; these contained nos, vip, nos/vip, npy, calr/calbindin (calb), sp or 5-ht. In the large intestine, there were five major classes of motor neurons that contained nos, nos/vip, gaba, sp, or calr/sp, and seven major classes of neurons that innervated myenteric ganglia and contained nos, vip, calr/calb, calr, sp, gaba or 5-ht. Although some aspects of the patterns of co-localisation are similar to those in other species, this study re-inforces recent analyses that indicate significant species differences in neurochemical patterns in the enteric neurons of different species.

Animals↗

Calretinin immunoreactivity of motor neurons in the guinea-pig distal colon and taenia coli.

Calretinin is a calcium-binding protein which occurs in neurons and endocrine cells, including neurons throughout the gastrointestinal tract. Calretinin-immunoreactive (IR) neurons innervate the circular muscle in the guinea-pig distal colon and have descending as well as ascending projections. This suggests that calretinin-IR is in motor neurons, but whether it might be in excitatory or inhibitory motor neurons or both was previously undetermined. The presence of calretinin-IR in neurons innervating the taenia coli has not been previously reported. Numerous fibres in the circular muscle of the distal colon and in the taenia coli displayed immunoreactivity for calretinin. Tachykinin (TK), vasoactive intestinal peptide (VIP), calretinin, and gamma-aminobutyric acid (GABA) immunoreactivity was also in fibres innervating these targets. The abundances of these fibres was estimated to be TK > VIP > calretinin > GABA. Double label immunohistochemistry revealed the presence in both tissues of populations of calretinin-IR fibres which were also TK-IR, and fibres with calretinin and GABA-IR in the colon, but calretinin-IR fibres were never VIP-IR. TK- and VIP-IR were in separate populations of nerve fibres as were GABA- and TK-IR. It is concluded that calretinin-IR does not provide a definitive labelling of a physiologically known subgroup of motor neurons, either in the distal colon or in the taenia coli, but that calretinin is most likely to be in excitatory motor neurons.

Animals↗