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Biomedical subjects

R M Quock

Publications and source records attributed to R M Quock.

At least 91 records · Page 5Linked to original sources
PubMed1978

Methylazoxymethanol acetate: effect of postnatal injection on brain amines and behavior.

The antimitotic drug, methylazoxymethanol acetate (MAMA), was injected into newborn rats during the first four days of life. At 48 days of age, these rats weighed one-third less than controls, as did the cerebella of their brains, but the rest of their brains weighed only 7% less than those of controls. The cerebella structures of the drug-injected rats was highly disorganized. Purkinje cells were scattered haphazardly in the granular layer instead of forming a monolayer. More foldings and short folia were found in the cerebella of drugged animals. In spite of these large morphological differences, the total amounts of norepinephrine and serotonin in the cerebella of the drugged rats were not different from those of the control rats. Behavioral effects of postnatal injection of MAMA include retarded development of the righting reflex,i.e., the drugged pups took longer time to right themselves when placed on their backs during the first nine days after birth; and scondly, MAMA reduced locomotor activity measured 45 days after birth.

Animals↗
PubMed1978

Tryptamine-induced drug effects insensitive to serotoninergic antagonists: evidence of specific tryptaminergic receptor stimulation?

The drug effects of tryptamine and 5-hydroxytryptopham (5-HTP) in the rabbit were compared following monoamine oxidase inhibition and various drug pretreatments. Both agents evoked hyperthermia and behavioural excitation; tryptamine but not 5-HTP also produced forepaw clonic activity. Serotoninergic receptor blockers abolished the effects of 5-HTP but only weakly influenced tryptamine responses. Both tryptamine and 5-HTP effects were potentiated by fluoxetine. Methergoline, a putative tryptaminergic receptor blocker, antagonized tryptamine-induced hyperthermia and forepaw clonus but did not influence 5-HTP responses. It is postulated that while 5-HTP produces its effects through a serotoninergic mechanism, some of the responses to tryptamine result from activation of a specific tryptamine-sensitive mechanism.

5-Hydroxytryptophan↗
PubMed1976

Differentiaton of neuropharmacological actions of apomorphine and d-amphetamine.

The dopaminergic agonists apomorphine and d-amphetamine elicit hyperthermic, hyperkinetic and stereotypic responses in the rabbit. The present investigation compares the influence exerted by various serotonergic antagonists upon these activities. Apomorphine-induced hyperthemia was antagonized by p-chlorophenylalanine (pCPA), cyproheptadine and cinanserin and was restored in pCPA-pretreated rabbits by regeneration of central serotonin levels, d-Amphetamine-induced hyperthermia was reduced by pCPA; restored in pCPA-pretreated animals by regeneration of central serotonin levels; and was uninfluenced by cyproheptadine and cinanserin. Apomorphine-induced locomotor stimulation was unaltered by serotonergic antagonists; however, these same doses of anti-serotonergic agents all markedly reduced d-amphetamine-induced hyperkinesia. Serotonergic antgaonists also failed to affect apomorphine-induced compulsive gnawing but did significantly enhance d-amphetamine-induced compulsive gnawing. It is concluded from these data that the neuropharmacological activities of apopmorphine and d-amphetamine in the rabbit differ in their dependence upon central serotonergic mechanisms.

Animals↗
PubMed1976

Fenfluramine-induced hyperthermia and stimulation in the rabbit.

Fenfluramine produces dose-related hyperthermia and behavioral stimulation in rabbits following intravenous administration. Both responses were antagonized by pretreatment with cinanserin, cyproheptadine, or fluxetine. Methergoline likewise abolished the stimulatory effect of fenfluramine and produced a partial blockade of the hyperthermia. Haloperidol was ineffective as a fenfluramine antagonist. This study demonstrates that fenfluramine-induced hyperthermia and stimulation in the rabbit result from an indirect action upon serotonergic receptors.

Animals↗