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Biomedical subjects

A Scriabine

Publications and source records attributed to A Scriabine.

At least 55 records · Page 3Linked to original sources
PubMed1977

Effects of phentolamine, phenoxybenzamine and desipramine on clonidine-induced blockade of cardiac acceleration in the dog.

Clonidine reduced cardiac acceleration induced by low frequency electrical stimulation of cardiac sympathetic nerve fibers in anesthetized and vagotomized dogs. This effect of clonidine was abolished by short periods of high frequency electrical stimulation. The inhibitory effect of clonidine was observed with 10- as well as with 90-sec periods of electrical stimulation of sympathetic nerve fibers; it was antagonized by phentolamine, phenoxybenzamine and desipramine. This suggests the presence of alpha-adrenoceptors at the peripheral sympathetic nerve ending in the dog.

Animals↗
PubMed1977

A comparison of the antiserotonin, antihistamine, and anticholinergic activity of cyproheptadine with analogues having furan nuclei fused to the 10,11-vinylene bridge.

A series of cyproheptadine derivatives having furan nuclei fused to the 10,11-vinylene bridge has been prepared. None of the compounds retain the potent antiserotonin and antihistaminic actions of cyproheptadine. 1-methyl-4-(1-methyl-8H-dibenzo[a,e]furo[3,4-c]cyclohepten-8-ylidene)piperidine (7), 1-methyl-4-(1,3-dihydro-1-oxo-8H-[3,4:6,7]cycloheptal[1,2-c]furan-8-ylidene)piperidine (10), and its reduction product 11 retained the peripheral anticholinergic activity of cyproheptadine.

Animals↗
PubMed1977

An approach to peripheral vasodilator-beta-adrenergic blocking agents.

The syntheses of 2-phenyl- and 2-pyridyl-4-trifluoromethylimidazoles having a 3-tert-butylamino-2-hydroxypropoxy moiety attached to the aryl or heteroaryl substituent are described. Structure--activity relationships based on results from an evaluation of these compounds for antihypertensive, vasodilating, and beta-adrenergic blocking activities are discussed.

Adrenergic beta-Antagonists↗
PubMed1977

(+)- and (-)-3-Methoxycyproheptadine. A comparative evaluation of the antiserotonin, antihistaminic, anticholinergic, and orexigenic properties with cyproheptadine.

The synthesis and resolution of (+/-)-3-methoxycyproheptadine [(+/-)-4] are described. As a peripheral serotonin antagonist, (+/-)-4 was found to be one-half as potent as cyproheptadine (1b). The peripheral anticholinergic and antihistaminic activities as well as the orexigenic property of (+/-)-4 are less than those of 1b. A further comparison of the enantiomers (+)-4 and (-)-4 shows that all of the anticholinergic activity of (+/-)-4 resides solely in the dextrorotatory enantiomer, (+)-4, while the antiserotonin activity, which is similar to that of 1b, resides in the levorotatory enantiomer, (-)-4. Antihistaminic and orexigenic activity also resides in (-)-4 but these properties are reduced compared to those of 1b.

Animals↗
PubMed1977

Saluretic and uricosuric effects of (6, 7-dichloro-2-methyl=1-oxo-2-phenyl-5-indanyloxy) acetic acid (MK-196) in the chimpanzee.

The saluretic and uricosuric responses elicited by a novel agent, MK-196, have been studied in a great ape, the chimpanzee. This agent is orally active at very low doses and has a prolonged duration of action. Probenecid does not appear to influence the saluretic and uricosuric properties of MK-196. Net tubular secretion of urate was reduced by MK-196. Urinary pH changes did not compromise the efficacy of this new agent. On a dose basis, MK-196 was more saluretic (and uricosuric) than ethacrynic acid or furosemide and possessed a longer duration of action. Because of the marked natriuresis caused by MK-196, some increase in potassium excretion occurred.

Animals↗
PubMed1976

Enhancement of the anti-hypertensive effect of methyldopa and other anti-hypertensive drugs by carbidopa in spontaneously hypertensive rats.

1. A peripheral inhibitor of L-aromatic amino acid decarboxylase, carbidopa [(-)-L-alpha-hydrazino-3,4-dihydroxy-alpha-methylbenzenepropanoic acid monohydrate], at doses up to 25 mg/kg intraperitoneally or 30 mg/kg orally had no effect on directly recorded arterial pressure of spontaneously hypertensive rats derived from the Wistar/Okamoto strain. It enhanced, however, the anti-hypertensive effects of methydopa, hydrallazine, guanethidine and clonidine, and, to a lesser extent, reserpine and hydrochlorothiazide. The mechanism of this enhancement is presently unkonwn, but biochemical studies support the assumption that carbidopa is likely to reduce sympathetic nervous system activity. 2. The conversion of [3H]tyrosine (given intraperitoneally) to dopa (3,4-dihydroxypheylalanine) and catecholamines was measured in the hearts and adrenals of control rats and animals pretreated with carbidopa (100 mg/kg, intraperitoneally). Carbidopa significantly decreased the accumulation of 3H-labelled catecholamines in both organs and increased their total tyrosine content and the specific radioactivity of tyrosine.

Animals↗
PubMed1976

Appetite stimulant activity of 3-carboxy-10,11-dihydrocyproheptadine.

The orexigenic and ancillary pharmacologic properties of 3-carboxy-10,11-dihydrocyproheptadine (CDC) were compared to those of cyproheptadine. The threshold dose, 0.0312 mg/kg p.o., of CDC for increasing food intake in the cat is similar to that of cyproheptadine, but CDC has a broader effective dose range, extending to 8 mg/kg p.o., compared with 1 mg/kg p.o. for cyproheptadine. Using an increase in food consumption of 20% or more as the criterion of a positive response, the dose effective in 50% of the animals was 0.35 mg/kg p.o. for both CDC and cyproheptadine. Both CDC and cyproheptadine possess a long duration of appetite-stimulant action, exceeding 18 hr following 0.5 mg/kg p.o. The ancillary pharmacologic properties of CDC are considerably reduced over those of cyproheptadine, except for antihistaminic activity, CDC being about two times more potent (protection against lethality in guinea-pigs exposed to an aeosol of histamine). As an anticholinergic in mice, CDC is greater than thirteen times less active than cyproheptadine as a mydriatic agent and greater than forty-two times less potent as an antagonist of oxotremorine-induced tremors. CDC retains only about 1/25 of the antiserotonin potency of the parent compound (inhibition of serotonin-elicited edema in the rat paw and 5-hydroxytryptophan provoked head twitch in rats). CDC reduced locomotor activity in rats to a significantly lesser degree than cyproheptadine. CDC thus is a more selective agent for the therapy of anorexia.

Animals↗
PubMed1975

Analysis of the hypotensive action of prazosin.

Results of animal studies indicate that the hypotensive effect of prazosin is due to vasodilatation which is dependent on two discernible components of drug action: (1) direct relaxation of vascular smooth muscle and (2) interference with peripheral sympathetic function at a site distal to the alpha-adrenergic receptor.

Animals↗