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S Symchowicz

Publications and source records attributed to S Symchowicz.

At least 55 records · Page 3Linked to original sources
PubMed1969

The effect of cocaine and imipramine on tyramine-induced release of noradrenaline-3H from the rat vas deferens in vitro.

1. Tyramine 10(-4)M significantly increased release of noradrenaline-7-(3)H (NA-7-(3)H) from rat vas deferens in vitro.2. Neither cocaine 10(-5)M nor imipramine 10(-7)M-10(-6)M significantly reduced tyramine-induced release of NA-7-(3)H.3. Increasing the exposure time to cocaine and imipramine from 10 to 20 min or pre-incubating the tissue with a wide range of NA-7-(3)H concentrations (3.3-333.3 ng/ml.) did not affect the lack of inhibition by cocaine and imipramine.4. It is suggested that the tyramine receptor in rat vas deferens differs from that in other systems and that blockade of tyramine-released noradrenaline at alpha-adrenergic receptors may be the most important mechanism for tyramine antagonism by imipramine-like drugs in this tissue.

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PubMed1968

The effects of drugs inhibiting catecholamine uptake on tyramine and noradrenaline-induced contractions of the isolated rat vas deferens.

1. Cocaine did not antagonize the tyramine-induced contractile response of the isolated rat vas deferens at the same concentrations which markedly potentiated the contractile response to noradrenaline.2. Imipramine and amitriptyline non-competitively antagonized the contractile response to tyramine but did not potentiate noradrenaline. Desmethylimipramine produced both potentiation of noradrenaline and antagonism of tyramine.3. Dexchlorpheniramine non-competitively antagonized the contractile response to tyramine. It also produced an atypical potentiation of noradrenaline in which lower concentrations of noradrenaline were potentiated to a greater extent than higher ones.4. Imipramine inhibited the in vitro uptake of noradrenaline-(3)H in rat vas deferens as did cocaine, desmethylimipramine and dexchlorpheniramine. These results suggest that the alpha-adrenergic blocking property of imipramine masks the potentiation of noradrenaline by uptake inhibition.5. Evidence is also presented which suggests that alpha-adrenergic blockade of released noradrenaline may be the major mechanism for tyramine inhibition by imipramine-like drugs. This may explain why cocaine, which has no real alpha blocking action, is ineffective against tyramine.

Animals↗