ADRENALINE & ITS ANTAGONIST

Abstract

Objective: This research work deals with the mechanism involved in determining the therapeutic
potential of adrenaline and its blockers in gastrointestinal motility. Method: The classical method of Craig & Clark was
used for obtaining the longitudinal and circular muscles strip of rabbit intestine for in-vitro studies. Each muscle strip
separately was subjected to the effect of adrenaline and its blockers. The results were recorded on polygraph
apparatus. Results: The effects were recorded in vice versa fashion i.e. agonist v/s antagonist and antagonist v/s
agonist on each muscle strip separately. Adrenaline had significant effect on the force of contraction of muscle strip.
On addition of antagonist in the presence of agonist the effects were increased. Longitudinal muscle showed more
pronounced effects i.e. 69% with beta-blocker in comparison to the effect with alpha-blocker, which was only 27%.
Circular muscle showed reduction in the force of contraction with adrenaline, which was further reduced on addition
of beta-blocker, whereas the effects were increased when treated with alpha-blocker. Conclusion: This study
concluded that adrenaline released in vitro in response to sympathetic stimulation or given from external source,
increases the force and reduces the rate of contraction. Hence decreases the intestinal motility due to its antispasmodic
effect. The result of this study can be utilized in the development of new drug related to G.I. motility mediated through
adrenoceptors.