Calcium modulatory properties of O,O-diphenyl O-N-cyclooctyl phosphoramidate [corrected] isolated from Ptychodiscus brevis in rat atria and smooth muscle.
Indian J Physiol Pharmacol
;
1997 Jul; 41(3): 257-62
Article
in English
| IMSEAR
| ID: sea-106715
ABSTRACT
Calcium modulatory activity of a marine toxin has been studied employing in vitro preparations. The toxin induced contracture in rat diaphragm was not modified by denervation, d-tubocurarine and tetrodotoxin (TTX). In contrast, varying concentrations of calcium, EGTA and ryanodine inhibited the contracture significantly. The toxin produced a series of repeating contractions in vas deferens. Experiments with TTX, adrenoceptor blockers and other agents exclude a release of neuromediators or direct stimulation of post synaptic receptors to account for the rhythmic effect in vas deferens. The dependence of rhythmicity on external Ca2+ concentration and inhibiting effect of Mn2+, ryanodine and nifedipine indicate a direct activation of voltage-sensitive calcium channel. The toxin also evoked a similar pattern of response in paced atria mediated through Ca2+ influx.
Full text:
Available
Index:
IMSEAR (South-East Asia)
Main subject:
Organophosphorus Compounds
/
Rats
/
Vas Deferens
/
Dinoflagellida
/
Male
/
Calcium
/
Atrial Function
/
Rats, Wistar
/
Cycloparaffins
/
Dose-Response Relationship, Drug
Language:
English
Journal:
Indian J Physiol Pharmacol
Year:
1997
Type:
Article
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