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J J Larsen

Publications and source records attributed to J J Larsen.

69 records · Page 4Linked to original sources
PubMed1981

Distribution and motor effect of VIP in female genital tract.

The distribution and concentration of vasoactive intestinal polypeptide (VIP) in different parts of the female genital organs from various species (cat, goat, pig, rabbit, rat, and guinea pig) were studied by means of immunohistochemistry and immunochemistry. In addition, the effect of VIP on the mechanical activity of uterine muscle was investigated in vitro. VIP immunoreactive nerve fibers innervating vessels and smooth muscle cells were fairly numerous in the genital organs of the cat and goat and less numerous in the pig, rabbit, rat, and guinea pig. In all species studied, VIP-containing nerves were most numerous in the cervix. The tissue concentration of VIP measured by immunochemistry was in agreement with the immunohistochemical findings. VIP inhibited the mechanical uterine activity in the cat, goat, pig, and rabbit, whereas only minimal effects were obtained in the rat and guinea pig. This difference between the species corresponded to the number of VIP-containing nerves in the uterine muscle. The data support the hypothesis that VIP may play a physiological role in the local nervous control of the uterine mechanical activity.

Animals↗
PubMed1981

Vasoactive intestinal polypeptide (VIP) in the male genitourinary tract: concentration and motor effect.

Vasoactive intestinal polypeptide (VIP) has previously been shown in nerves of the male and female genitourinary tract, appearing to innervate vascular and nonvascular smooth and epithelial cells. In the present study the concentration of VIP in tissue extracts of different parts of the male genitourinary tract from cat and man was determined by radioimmunoassay. In addition, the effect of VIP on the contractility of the smooth muscle from the cat genitourinary tract was investigated in vitro. The tissue concentrations of VIP were generally higher in cat than in man. In both species high concentrations were found in the vas deferens, bladder, urethra and prostate, In concentration from 3 x 10(-8) to 6 x 10(-7) mol x 1-1, VIP inhibited in a concentration-dependent manner the muscle contractions in specimens from all regions examined, i.e., the vas deferens, ureter, corpus of the bladder, and urethra. The data indicate that VIP might play a physiologic role in the local nervous control of the smooth muscle activity in the male genitourinary tract.

Adult↗
PubMed1980

Effects of VIP in the female genital tract.

Vasoactive Intestinal Polypeptide (VIP) has been demonstrated in the female genitourinary tract, localized in neurons which seem to innervate vessels and non-vascular smooth muscle. The present work has demonstrated that the concentration of immunoreactive VIP varies between different mammalian species and within the genital tract of the same species. Using various in vivo and in vitro preparations the peptide was found to have a dose-dependent inhibitory effect on the myoelectrical activity and contractility of the uterine muscle, and to increase myometrial blood flow. The findings support the hypothesis that VIP may play a physiological role in the local control of uterine motility and blood flow.

Animals↗
PubMed1979

alpha And beta-adrenoceptors in the detrusor muscle and bladder base of the pig and beta-adrenoceptors in the detrusor muscle of man.

1 The presence and type of adrenoceptors in the smooth muscle of the pig and human urinary bladder was assessed on the basis of the relative potency of alpha- and beta-adrenoceptor agonists and antagonists.2 In isolated, carbachol-contracted bladder strips from the pig detrusor muscle the relaxing potency of isoprenaline was four times that of salbutamol and ritodrine and thirty times that of noradrenaline.3 Propranolol caused a parallel shift to the right of the noradrenaline dose-response curve which was not changed by phentolamine.4 Propranolol and butoxamine showed, in contrast to practolol, a dose-dependent antagonism of the response to isoprenaline. A pA(2) value of 9.2 +/- 0.2 and 6.8 +/- 0.2 (mean +/- s.e. mean) for the first two antagonists was calculated.5 In the bladder base of the pig, propranolol caused a parallel shift to the right and phentolamine a shift to the left of the dose-response curve to noradrenaline.6 In the human detrusor muscle the potency and maximum effect of isoprenaline and salbutamol were less than those in the pig detrusor muscle. The potency of isoprenaline was sixty times that of salbutamol.7 Whereas a parallel shift to the right of the dose-response curve to isoprenaline was obtained with propranolol, no antagonism was obtained with butoxamine or practolol.8 The results are interpreted as indicating the presence of beta(2)-adrenoceptors in the detrusor muscle of the pig and beta-adrenoceptors with neither beta(1)- nor beta(2)-characteristics in the detrusor muscle of man. An indication of the presence of alpha-adrenoceptors in the bladder base but not in the detrusor muscle of the pig was obtained.

Adult↗
PubMed1979

Beta-adrenoceptors in the pregnant and non-pregnant myometrium of the goat and cow.

The muscle relaxing effect of beta-adrenoceptor agonists was examined without and with the presence of beta-adrenoceptor antagonists in strips from the pregnant and non-pregnant myometrium of the goat and from the pregnant myometrium of the cow. Isoprenaline, salbutamol and ritodrine caused a dose-dependent reduction of the spontaneous contractions of the pregnant myometrium and a dose-related and parallel shift to the right of the isoprenaline dose-response curve was obtained with butoxamine but not with practolol. Isoprenaline but neither salbutamol nor ritodrine caused a dose-related reduction of the spontaneous contractions in the non-pregnant myometrium and a dose-related and parallel shift to the right of the dose-response curve of isoprenaline was brought about with propranolol but not with either butoxamine or practolol. The muscle relaxing effect of ritodrine on the pregnant myometrium of the goat and cow shown in vitro was also demonstrated in vivo in the same species within eight hours of delivery. It is concluded that the beta-adrenoceptors in the pregnant myometrium of the goat and cow belong to the beta2-group whereas those in the non-pregnant myometrium cannot be classified as either beta1- or beta2-adrenoceptors.

Albuterol↗
PubMed1978

Effect of ritodrine on the bladder capacity in unanaesthetized pigs.

A cystometric investigation was carried out in unanaesthetized pigs. During intravenous infusion of ritodrine (10, 30 and 50 microgram/kg/min.) a dose-dependent and significant increase of the bladder capacity was obtained. A concomitant significant elevation of the heart rate followed the administration of the drug.

Animals↗
PubMed1978

Sympathetic innervation of the urinary bladder and urethral muscle in the pig.

The sympathetic innervation of the lower urinary tract was studied in the female and male pig using a specific histochemical technique for visualization of noradrenaline containing nerves. In smooth muscle from the detrusor few evenly distributed adrenergic nerve terminals were found. A greater number of terminals were observed in the trigone, bladder neck and urethra. There was no sex difference. In smooth muscle specimens from pig detrusor and trigone sympathetic nerve terminals were more abundant than in corresponding tissue from humans.

Animals↗
PubMed1977

Pharmacodynamics of a new selective beta2-adrenergic bronchodilator 3-(4-methoxybenzylamino)-4-hydroxy-alpha-(tert. butylaminomethyl)-benzyl-alcohol, HCl (QH25).

The bronchodilator effect of QH25 (3-(4-methoxybenzylamino)-4-hydroxy-alpha-(tert. butylaminomethyl)benzylalcohol, HCl) a new beta2-adrenergic bronchodilator has been investigated in conscious guinea pigs and in anaesthetized guinea pigs and cats and compared to that of salbutamol and isoprenaline. In anaesthetized guinea pigs QH25 and isoprenaline were equipotent after intravenous administration, whereas salbutamol was four times less active. The same difference between QH25 and salbutamol was observed after intraduodenal administration. After oral administration in conscious guinea pigs QH25 was eight and five times more potent than salbutamol and isoprenaline respectively, whereas no difference was observed when the agents were administered as aerosols. The bronchodilator action of QH25 was apprxomately three times that of salbutamol in egg-albumine sensitized guinea pigs after oral administration. In anaesthetized cats the bronchodilator potency of QH25 was three times that of salbutamol and the same or slightly higher than that of isoprenaline. A half-life of 4 hours for the bronchodilator action in guinea pigs was determined for both QH25 and salbutamol after oral administration. The effect of QH25 and salbutamol on cardiovascular parameters i.e. chrono- and inotropic action and blood pressure decreasing effect in guinea pigs, cats and dogs was essentially the same whereas isoprenaline was from 5 to 30 times more potent. The potential tremorogenic action of QH25 estimated on the cat soleus muscle was eight times less than that of isoprenaline and the same or slightly less than that of salbutamol. From the experimental data it is concluded that QH25 has the same potency as isoprenaline as a bronchodilator agent but is more potent than salbutamol. Taking into account that isoprenaline is considerably more active on cardiovascular parameters and on the cat soleus muscle than QH25 which has the same or less effect than salbutamol on these parameters the data suggest that QH25 is a more selective bronchodilator agent than both isoprenaline and salbutamol.

Acetylcholine↗
PubMedDate not supplied

Total number and mean cell volume of neocortical neurons in rats exposed to 2,5-hexanedione with and without acetone.

The toxicological effects of 2,5-hexanedione (2,5-HD) alone and combined with acetone on the number and size of neurons in the cerebral cortex of rats were evaluated with stereological techniques. Thirty rats were equally divided into three groups: One control, one receiving 0.5% 2,5-HD, and one receiving 0.5% 2,5-HD and 0.5% acetone in the drinking water for seven weeks. Unbiased estimates of the total number of neocortical neurons, as well as the mean neuronal nuclei and cell body volumes were obtained from systematically sampled 3.5-microns sections. The total number of neurons in the 2,5-HD group was significantly smaller than the control group (p less than 0.05, one-tailed t-test). Both test groups showed significant changes in the mean cell body volume: Compared with the control group, animals exposed to 2,5-HD had 11% smaller cell body volumes while animals exposed to 2,5-HD and acetone had 13% larger cell body volumes. These data represent the first unbiased estimation of mean cell volume in toxicology. We propose the nucleator method as an efficient and accurate tool for estimating quantitative changes in toxicological research.

Acetone↗
PubMedDate not supplied

Effects of 2,5-hexanedione alone and in combination with acetone on radial arm maze behavior, the "brain-swelling" reaction and synaptosomal functions.

A multidisciplinary study to investigate 2,5-hexanedione (2,5-HD)-induced CNS-neurotoxicity and its proposed potentiation by acetone (AC) was conducted. Neurobehavioral testing, estimation of the brain-swelling reaction, neuropathological and morphometric measurements as well as synaptosomal 5-hydroxytryptamine (5-HT) uptake were evaluated. Male Wistar rats were exposed through their drinking water, for seven weeks, either to 0.5% 2,5-HD alone or to 0.5% 2,5-HD in combination with 0.5% AC. This 2,5-HD dose is known to cause neurotoxicity in the peripheral nervous system. Exposed animals were compared to a control group that received tap water. Acquisition but not performance of spatial learning, as measured in the radial 8-arm maze, was significantly inhibited by the coexposure to 2,5-HD and AC. Brain weights of rats exposed to 2,5-HD alone and to 2,5-HD and AC in combination, were slightly, albeit significantly, reduced. Synaptosomal high-affinity 5-HT uptake rate and uptake capacity were significantly reduced by 2,5-HD alone and in combination with AC. The morphometric results are reported in a companion paper. In conclusion, the present findings indicate that 2,5-HD is a CNS-neurotoxicant. The hypothesis about AC potentiation of 2,5-HD CNS-neurotoxicity was supported.

Acetone↗
PubMedDate not supplied

In utero reproductive study in rats exposed to nonylphenol.

Alkylphenol ethoxylates are widely used non-ionic surfactants. Nonylphenol ethoxylate constitutes 82% of the production of all alkylphenol ethoxylates and the breakdown product of nonylphenol ethoxylate, nonylphenol (NP) has been shown to be estrogenic in both in vitro and in vivo screening assays. To determine the potential reproductive toxicity of NP, a one-generation in utero study was conducted. Rats were dosed from gestation day 11 through 18 with NP at 3, 15, or 75 mg/kg/day or diethylstilbestrol (DES) at 30 microg/kg/day. DES was used as a positive control. Both substances were given orally by gavage. Male offspring were sacrificed at postnatal day (PND) 11, 21, or 110 and reproductive parameters were evaluated. Pup birth weight and body weight and percent motile sperm at age of 110 day were significantly reduced by DES. The absolute weight of the right epididymis was significantly reduced in the DES group. The absolute weight of the right epididymis were also significantly decreased in the animals exposed to 75 or 15 mg/kg/day NP, effects which disappeared when organ weight was related to body weight. This study showed a dose-dependent effect of nonylphenol on male reproductive development at doses of 75 and 15 mg/kg bw/day based on absolute epididymal weight.

Animals↗
PubMedDate not supplied

Acetone potentiation and influence on the reversibility of 2,5-hexanedione-induced neurotoxicity studied with behavioural and morphometric methods in rats.

The neurobehavioural and morphologic changes and the reversibility in 2,5-hexanedione-induced polyneuropathy in rats were studied. The potentiation and influence of acetone on the reversibility of the induced neurotoxicity was also evaluated. Male rats were treated for 6 weeks with 0.5% w/v 2,5-hexanedione alone or in combination with 0.50% w/v acetone in the drinking water. During the treatment period, neurobehavioural tests (ambulation and rearing in open field, balance on the accelerating rotarod and fore-and hindlimb muscle strength measurements) were performed weekly. After 6 weeks half of the rats was sacrificed and histopathological lesions in the sciatic nerve and tibial nerve were evaluated by morphometry. Neurotoxicity was induced by 2,5-hexanedione, and acetone caused a potentiation of this effect in open field ambulation and rearing and in the rotarod test. In the pathological evaluation, giant axonal swelling was observed after 2,5-hexanedione and 2,5-hexanedione plus acetone. In nerve fibre cross sections, a significant change of the distribution of fibre area size was observed in animals treated with 2,5-hexanedione. Aggravation of the lesions was seen in rats treated with both 2,5-hexanedione and acetone. The other half of the animals was used to study the reversibility of the neurotoxic effects within a dose-free period of 10 weeks. Reversibility of the effect on ambulation was complete within the recovery period, but the effects on rearing and balance in the rotarod test were only reversible within the 10 weeks in the 2,5-hexanedione-treated rats and not in the combined 2,5-hexanedione and acetone-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetone↗