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Biomedical subjects

M Sokolovsky

Publications and source records attributed to M Sokolovsky.

At least 181 records · Page 10Linked to original sources

On the interaction of drugs with the cholinergic nervous system. II. Cross-tolerance between phencyclidine derivatives and cholinergic drugs.

A symmetrical cross-tolerance was found between two phencyclidine derivatives--phencyclidine and cyclohexamine--and also between two cholinergic drugs--physostigmine and oxotremorine. On the other hand, mice rendered tolerant to the phencyclidine derivatives showed cross-tolerance to these cholinergic drugs, but no cross-tolerance was observed in the opposite direction. The applicability of such experiments to the elucidation of neurochemical interactions of centrally acting drugs is discussed.

Animals↗

Proteolytic proenzymes in the pancreas in the course of experimental bile-induced pancreatitis in the guinea pig.

The levels of the proenzymes trypsinogen and chymotrypsinogen were studied in guinea pigs with pancreatitis induced by injection of sodium taurocholate containing the antibiotic cephalothin. This treatment inhibited the enzyme activities and prolonged the activation times of the proenzymes. Both trypsinogen and chymotrypsinogen content decreased after induction of pancreatitis, but there were no significant changes in the proenzyme contents in relation to injection-to-excision times. Sodium taurocholate and cephalothin were cleared from the pancreas in 2 h. Administration of chlorophyll-a together with the inducer caused a slight increase in proenzyme levels.

Animals↗

Anticholinesterase and antiacetylcholine activity of 1-phenylcyclohexylamine derivatives.

The antiacetylcholine and anticholinesterase potencies of four 1-phenylcyclohexylamine derivatives were estimated by measuring their antagonism to the contractile response of smooth and striated muscles and their inhibition of cholinesterase activity. In addition, their affinities towards the central muscarinic receptor from mouse brain homogenate were determined by competition experiments in vitro. Relative to atropine, these drugs exerted mild antimuscarinic activity in both isolated smooth muscle and in the competition experiments. On the other hand, they were found to exert antinicotinic potencies equal to that of d-tubocurarine in the striated muscle. The concentration of (3H)-phencyclidine taken up by mouse brain in vivo could be correlated with its dissociation constants from the central muscarinic binding sites, as well as with the Ki values for acetylcholinesterase inhibition, both determined in vitro. Since these drugs have a similar rigid spatial molecular structure, it is proposed that the variations in the potency of their cholinergic interactions stemmed mainly from the structural changes in the region of the 'cationic head'.

Acetylcholine↗

Antimuscarinic properties of antidepressants: dibenzepin (Noveril).

The antimuscarinic potency of dibenzepin (Noveril) was estimated by measuring (a) central in vivo effects in mice (antihypothermia and antitremor, both induced by oxotremorine), (b) peripheral in vivo activity (mydriasis caused by systemic administration of the drug), (c) the effects of dibenzepin on isolated smooth muscle from guinea pig ileum, and (d) in vitro determination of the affinity constant of dibezepine toward the muscarinic binding sites in whole mouse-brain homogenate. The data allowed the construction of a normalized antimuscarinic potency scale for some of the common tricyclic antidepressants. With a value of 1 for scopolamine, the following relative anticholinergic potencies were calculated: dibenzepin--1/600, nortriptylne--1/300, imipramine - 1/200, and amitriptyline - 1/75. These values suggest an explanation for the absence of clinically detectable anticholinergic side effects during treatment of depression with high doses of dibenzepin. Structural and spatial interrelations among various tricyclic antidepressants and scopolamine are discussed.

Animals↗