Evidence for the inhibitory effect of 5-hydroxytryptamine at central and peripheral sites on ovulation in rabbits

1. The effect of 5-hydroxytryptamine (5-HT) has been investigated on ovulation per se as well as on induced ovulation in rabbits. 2. 5-HT administered intracerebroventricularly (i.c.v.) did not induce ovulation per se. 3. The ovulation was induced by coitus, subcutaneous administration of progesterone and intravenous administration of cupric acetate. 4. Postcoital and progesterone induced ovulation was found to be blocked by i.c.v. administered 5-HT. 5. Cupric acetate induced ovulation was, however, not found to be blocked by i.c.v. administered 5-HT. 6. Intraperitoneal administration of 5-HT was found to block cupric acetate induced ovulation. 7. It is concluded that 5-HT exerts an inhibitory control over ovulation by acting at central as well as at peripheral sites in rabbits.

Diurnal variations in lung transfer factor and its components

Serial measurements of transfer factor of lung and its constituent components along with FVC and EFR25-75% were undertaken in 20 healthy nonsmoker adult males thrice on the same day. All the lung transfer components decreased as the day advanced, though reduction was statistically significant for Tlco and VA only. These changes were present in association with reduction in FVC and EFR25.75% indicating that patency of airways influences diffusion function of lung. Variations during the day are less than 7.4% and are hence unlikely to influence their diagnostic value, but serial estimation of these functions should preferably be carried out at the same time specially in the morning when these values are maximum.

Response of lung transfer components to grades of smoking

Pulmonary functions were studied in 50 healthy, asymptomatic, 20 to 47 years, male smokers along with 50 healthy non-smokers matched for age, height, socio-economic status and physical activity. Smokers consumed 2-30 cigarettes per day with duration of smoking ranging from 2 to 26 years. In smokers FEF, V75. PEF and MVV were significantly reduced whereas FRC was increased significantly. Pulmonary diffusion function as assessed by TLCO showed significant reduction. While Vc showed progressive decrease with increasing duration and quantity of smoking, DM increased in the beginning but gradually declined later. TLCO showed a better negative correlation with quantity than with duration of smoking even when the effect of other factors was excluded. Decrease in TLCO is probably due to bronchoconstriction and reflex vasospasm of pulmonary vasculature. Co-efficient of diffusion KCO was also decreased in smokers.

Nervous system in Olveria indica, a rumen paramphistome (Digenea) of bovines, as revealed by non-specific esterase staining

On the basis of esterase localization the complete nervous system has been visualized in Olveria indica Thapar & Simha, 1945, a paramphistome from the rumen of cattle, recorded for the first time from the north-east region of India. The basic number of posterior longitudinal nerves (i.e., 3 pairs) is the same as in other paramphistomes; four pairs of anterior longitudinal nerves are present, there being an extra pair of pharyngeal nerves. Conspicuous differences in the innervation patterns were observed, mainly in the innervation of the genital atrial region and acetabulum. The presence of prominent longitudinal connections, joining the anterior and posterior dorsal nerves and the anterior and posterior ventral nerves on either side, is a feature not hitherto found in other paramphistome species. The details of the course of all the nerves and their branches are discussed.

A comparison of alpha 2-adrenoceptor regulation in brain and platelets

Functional responses and alpha 2-adrenoceptor radioligand binding were studied in brain and platelets of rabbits under a variety of circumstances. The effects of oestrogen treatment and maturation were studied in female rabbits and of aging and amitriptyline treatment in male rabbits. No correlation was found between changes in brain and platelets either in response or alpha 2-adrenoceptor ligand binding under any of the conditions examined.

Alpha-adrenoceptor changes after oestrogen treatment in platelets and other tissues in female rabbits

alpha 2-Adrenoceptors on blood platelets have been widely used as a model for alpha-adrenoceptors in less accessible tissues. The effect of oestrogen (200 micrograms/day intramuscularly) on alpha 2-adrenoceptor number and function was studied in immature female rabbits. alpha 2-adrenoceptor number was measured in whole platelets, and membrane preparations of forebrain, hindbrain, spleen and kidney by radioligand binding. alpha 2-Adrenoceptor function was examined by measuring platelet aggregation in vitro and circulatory responses to selective alpha 2-adrenoceptor agonists in vivo. Oestrogen treatment resulted in a significant decrease in platelet alpha 2-adrenoceptor number and function. However, no changes were observed either in receptor number in other tissues or in responses to alpha 2-agonists in vivo. The results suggest that oestrogen modulation of rabbit platelet alpha 2-adrenoreceptor number and function may be different from that of brain, kidney and spleen. Caution should be exercised in extrapolating results from platelets to alpha-adrenoceptors at other sites.

The effects of sexual maturation on alpha-adrenoceptors in female rabbits

alpha-Adrenoceptor number and function were examined in brain, platelets, and other peripheral tissues of young (2-3 months) and mature (6-8 months) non pregnant female rabbits. alpha1-Adrenoceptor number was significantly higher in forebrain, hindbrain, spleen and heart of mature rabbits. alpha2-Adrenoceptor number, on the other hand, was found to be significantly lower in platelets, forebrain and spleen but not changed in hindbrain and kidney of mature animals compared to young females. There was a significant reduction in platelet aggregation with maturation. However, no change in in vivo pressor or depressor responses to alpha-adrenoceptor agonists was observed in vivo.

Presence of cholinoceptors in mesencephalic raphe nuclei concerned in thermoregulation in rabbits

The thermal effects of cholinomimetics and cholinoceptor blocking agents microinjected into mesencephalic nucleus raphe medianus (NRM) were investigated in rabbits to determine the nature and role of these cholinoceptors in thermoregulation. Microinjection of cholinoceptor agonists, carbachol and pilocarpine, into NRM resulted in significant hyperthermia which could be blocked by local pretreatment with chlorisondamine (a nicotinic receptor blocker) as well as by ethybenztropine (a muscarinic receptor blocker). Intracerebroventricular pretreatment with LM 5008 (serotonin reuptake blocker) significantly inhibited the carbachol-induced hyperthermia. Both nicotinic and muscarinic cholinoceptors are present in mesencephalic NRM which may be involved in thermoregulation in rabbits. Activation of these cholinoceptors in NRM results in hyperthermia which seems to be due to an inhibition of a serotonin sensitive hypothalamic heat loss mechanism.

Effects of morphine and pethidine on coronary vascular resistance, blood pressure, and myocardial infarction-induced cardiac arrhythmias

In the present study, the effects of morphine and pethidine on coronary vessel resistance (CPP), blood pressure (BP), and experimental myocardial infarction-induced cardiac arrhythmia were investigated. Both morphine and pethidine induced a fall in CPP and BP and inhibited the cardiac arrhythmia. The morphine effects on CPP and BP were largely blocked by mepyramine. The effects of pethidine, on the other hand, were not blocked by mepyramine, propranolol, or atropine. An interesting dose dependent inhibition of cardiac arrhythmia was observed with pethidine.

Lactic acid production from molasses by Lactobacillus bulgaricus AU in presence of U, Th, Zr, and Tl

The influence of uranium, thorium, zirconium, and thallium (I) on fermentation production of lactic acid from molasses by Lacstobacillus bulgaricus AU was studied. It was found that thorium, at lower experimental concentration, and zirconium, at higher experimental concentration, stimulate the acid-producing activity of the bacteria, while uranium and thallium reduce. it.

Fermentative production of lactic acid in presence of some trace elements

An attempt was made to study the activity of Lactobacillus delbrueckii under the influence of certain trace elements, viz. Tl, U, Th, and Zr. From the results, it was inferred that Tl has comparatively more stimulating effect on the acid-producing activity of the bacteria than U, Th, and Zr.

Influence of EDTA and its metal complexes on lactic acid fermentation

A comparative study of the influence of EDTA and its metal complexes with Fe, Co, and Ce on lactic acid fermentation by Lactobacillus delbrueckii was done. It was observed that EDTA alone and its complex with Ce could increase the yield of lactic acid up to 1--2%, while complexes of EDTA with Fe and Co enhanced the yield up to 4--5%.

Lactic acid production from molasses by mixed population of lactobacilli

The production of lactic acid from molasses by mixed populations of (1) Lactobacillus bulgaricus AU (isolated from curd) and L. casei (supplied by NCL, Poona-8, India) and (2) L. bulgaricus, L. delbrueckii (supplied by NCL, Poona-8, India), and L. casei was studied. It has been found that association of L. bulgaricus with L. casei slightly enhances the yield of lactic acid, while the mixed population of L. bulgaricus, L. delbrueckii, and L. casei is as effective as L. bulgaricus alone.

Partial inhibition of postreplication repair and enhanced frequency of chemical transformation in rat cells infected with leukemia virus

Postreplication repair of DNA and chemical transformation with the carcinogen 4-nitroquinoline-1-oxide were studied in rat cell lines either uninfected or infected with Rauscher leukemia virus. The results indicate that equivalent amounts of carcinogen are bound to the DNA initially and removed during excision repair. However, the lines differ in that the infected line alone exhibits both sensitivity to nitroquinoline-oxide-induced transformation and a partial inhibition of the postreplication repair process after notroquinoline oxide or UV treatment.

An analysis of central adrenoceptors for control of cardiovascular function

1. In dogs anaesthetized with pentobarbitone sodium, bradycardia with hypotension occurred on intracerebroventricular (i.c.v.) injection of noradrenaline (50-200 mug) or phenylephrine (100-400 mug), but tachycardia with hypotension occurred on i.c.v. injection of isoprenaline (100-200 mug).2. These cardiovascular responses were central effects, and from the results obtained after bilateral vagotomy, removal of both stellate ganglia and transection of the upper cervical cord, it was evident that the efferent nervous pathway for all these effects was the sympathetic nervous system.3. An i.c.v. injection of the alpha-adrenoceptor blocking agent phenoxybenzamine (10 mg) blocked the bradycardia and hypotension produced by noradrenaline or phenylephrine, and an i.c.v. injection of a beta-adrenoceptor blocking agent, either propranolol (2 mg) or N-isopropyl-p-nitrophenyl-ethanolamine (INPEA) (10 mg), blocked the tachycardia and hypotension produced by isoprenaline.4. The cardiovascular effects produced by i.c.v. injection of the three sympathomimetic amines could be reproduced in cross-circulation experiments in the recipient dog when the amines were injected into its head circulation, and the effects of noradrenaline and phenylephrine, but not those of isoprenaline, were abolished by the alpha-adrenoceptor blocking agent yohimbine (1 mg/kg) injected intravenously into the donor dog.5. It is concluded that the central alpha-adrenoceptors are concerned with bradycardia and the central beta-adrenoceptors with tachycardia, but that both receptors are concerned with hypotension.