| RESEARCH PAPER
|Year : 1993 | Volume
| Issue : 4 | Page : 228-233
Studies on post-receptor mechanisms in smooth muscle preparations
AA Mehta, KC Dave, RK Goyal
The possible role of calmodulin and phosphatidyl- inositol cycle which are finally involved in the excitation- contraction coupling, has been explored using W7 [N- (aminohexyl)-5-chloro-l-naphthalene sulphonamide], a specific calmodulin antagonist and lithium chloride(LiCI), the inositol monophosphatase inhibitor. Noradrenaline (NA), phenylephrine (PHE), indanidine (IND), 5- hydroxytryptamine (5-HT), dopamine (DA) and acetylcholine (Ach) produced dose dependent contractions of rat anococcygeus muscle and rat vas deferens. The responses to all the agonists were significantly reduced in the presence of LiCl (7.7 x IO-7 M) with the reduction-in maxima in both the preparations except that of DA in rat vas deferens. In the presence of W7 (6.8 x 10-7M), the responses to all the agonists except DA and Ach were significantly inhibited in rat anococcygeus muscle whereas, in rat vas deferens responses to none of the agonists were altered. The data supports the involvement of calmodulin as well as phosphatidyl inositol cycle in rat anococcygeus muscle. In rat vas deferens, calmodulin does not seem to be involved, however, involvement of phosphatidyl inositol cycle cannot be ruled out in this preparation.
A A Mehta
Source of Support: None, Conflict of Interest: None