Biomedical subjects

S K Bapat

Publications and source records attributed to S K Bapat.

24 records · Page 2Linked to original sources

PubMedDate not supplied

Central cholinergic mechanism for control of urine volume and electrolyte excretion.

1. Studies were conducted on urine volume and electrolyte excretion chiefly of Na and K in anaesthetized hydrated dogs. 2. Central injection of acetylcholine caused a dose dependent antidiuretic response but without any change in excretion of urinary Sodium (UNa) and Potassium (UK). 3. After central atropinization, antidiuretic response to acetylcholine was partially blocked without any effect on electrolyte excretion. 4. Intracerebroventricularly (I.C.V.) administered acetylcholine after vagotomy and spinalectomy, each done separately and together also elicited an antidiuretic response. There was no effect on electrolyte excretion. 5. It is thus suggested that acetylcholine may be acting on central cholinergic receptors concerned with A.D.H. release.

Acetylcholine↗

PubMedDate not supplied

Effect of centrally administered insulin on blood glucose levels in dogs.

The effects of minimal doses of insulin administered by intracerebroventricular (ICV) and intracisternal (IC) routes in mongrel dogs, on peripheral blood glucose level (BGL) have been studied. The dose of 0.1 U of insulin was found to be the minimal dose. This dose produced an immediate short lived hyperglycaemia followed by a marked and sustained hypoglycaemia. Both the effects were not observed in spinal cord transected-vagosympathectomised animals. The immediate hyperglycaemic effect was not observed in adrenalectomised animals whereas the subsequent hypoglycaemic effect did not appear only when the liver was removed. In an attempt to identify the precise site of action in the central nervous system (CNS), The cerebellomedullary angles were found to be the most sensitive sites for the action of locally applied insulin. It is suggested that insulin on central administration causes a rise in the BGL by an action on the adrenal glands and subsequently causes a marked fall in BGL by an action on the liver through some nerve fibers.

Adrenalectomy↗

PubMedDate not supplied

A pharmacological study of the effect of adrenaline, noradrenaline and acetylcholine on kidneys.

The effects of different doses of adrenaline, noradrenaline and acetylcholine administered intravenous intrarenal and intra-cerebro-ventricular routes were studied on the urine out put in dogs. The findings are correlated with the known haemodynamic actions of these neurohumors as well as their direct actions on the reabsorptive mechanisms of the renal tubules. The effects of ICV administration are possibly due to the liberation of A.D.H. from posterior pituitary.

Acetylcholine↗

PubMedDate not supplied

Actions of glucagon on the perfused vessels of the isolated rabbit ear.

Actions of glucagon on the perfused vessels of the isolated rabbit ear were investigated. The two main actions of glucagon on the perfused ear vessels of the rabbit are: (i) release of noradrenaline which accounts for the constrictor response in low tone preparations. The response depends on the level of 3, 5 AMP. If the level rises as a result of noradrenaline action, contriction sets in. (ii) Glucagon may stimulate the adenylcyclase. In the high tone preparation 3,5 AMP levels are probably high. Release of noradrenaline by glucagon would have little additonal effect.

Animals↗

PubMedDate not supplied

Effects of centrally administered insulin on urine output and sodium excretion in dogs.

The effects of insulin administration via intracerebroventricular (ICV), third ventricular (TV) and intracisternal (IC) routes on the urine output and sodium excretion have been studied in mongrel dogs. The central administration of insulin resulted in a significant increase in urine output and sodium excretion. This diuresis and natriuresis was not observed in animals which had undergone either spinal-cord transectomy or adrenalectomy. The insulin-sensitive receptors for this diuresis and natriuresis seem to be present in the vicinity of the fourth-ventricle of the brain. The observations in the present study suggest that the probable efferents might be the sympathetic fibers in the spinal-cord. The centrally administered insulin inhibits the secretion of some substance from the adrenal cortex, which in turn results in the diuresis and natriuresis in animals.

Adrenalectomy↗

PubMedDate not supplied

Centrally mediated hypocholesterolaemic response of insulin in dogs.

Insulin on intravenous administration in dogs caused a rise in blood cholesterol level. This may be due to its direct action on liver or other peripheral structures. On the other hand, insulin administered into the lateral cerebral ventricles in normal as well as in spinal and vagotomized dogs resulted in a lowering of blood cholesterol. In cross circulation studies insulin administered into lateral cerebral ventricles of donor dogs produced a hypocholesterolaemia in the recepient dogs without significant changes in blood cholesterol of donor dogs. It is suggested that some substance may be liberated from some parts of central nervous system due to an action of centrally administered insulin. This substance in turn causes hypocholesterolaemia by acting on liver or some other peripheral structures in dogs.

Animals↗