Interaction of calcium channel blockers (CCBs) with histamine and 5-hydroxytryptamine in aorta from normal and diseased rats

The present study attempts to investigate the interaction of calcium channel blockers (CCBs) with histamine (H) and 5-hydroxytryptamine (5-HT) in rat isolated aortic strip preparations. In preparations obtained from rats chronically treated with various CCBs the contractile responses to H were compl...

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Bibliographic Details
Published in:Indian journal of physiology and pharmacology 1996-04, Vol.40 (2), p.120
Main Authors: Bhugra, P, Gulati, O D
Format: Article
Language:English
Subjects:
Animals
Aorta, Thoracic - drug effects
Calcium Channel Blockers - pharmacology
Desoxycorticosterone
Histamine - pharmacology
Hypertension - chemically induced
Hypertension - physiopathology
Hyperthyroidism - chemically induced
Hyperthyroidism - physiopathology
In Vitro Techniques
Male
Muscle, Smooth, Vascular - drug effects
Rats
Rats, Wistar
Serotonin - pharmacology
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Summary:The present study attempts to investigate the interaction of calcium channel blockers (CCBs) with histamine (H) and 5-hydroxytryptamine (5-HT) in rat isolated aortic strip preparations. In preparations obtained from rats chronically treated with various CCBs the contractile responses to H were completely blocked suggesting that this may be due to inhibition of the voltage-dependent channels and inositol 1,4,5-triphosphate induced release of calcium from intracellular stores. The decreased contractions of the aortic strip preparations with 5-HT obtained from rats chronically treated with various CCBs implies a decrease in 5-HT receptor density. DOCA-saline hypertensive rats chronically treated with various CCBs showed variable responses to H and 5-HT suggesting that these changes may be due to different isoforms of L-type calcium channels. In L-thyroxine-treated preparations or those simultaneously treated with L-thyroxine and CCBs the responses to H were abolished and those to 5-HT were partially blocked with decrease in maxima which could be secondary to the primary effect on the heart and to generalised reduced senstivity of the rat aorta.
ISSN:0019-5499