The Relation Of Carbachol-Induced Contraction With Calcium And The Inhibitor Effects Of Some Muscarinic Antagonists In Isolated Rabbit Detrusor Muscle.

In this in vitro study, the inhibitory effect of verapamil on the responses obtained with calcium on the carhachol induced contractions. In Ca2+ -free medium and the relaxation effects of atropin, amitriptyline and maprotiline on the same contraction in the medium with normal solution in isolated rabbit detrusor muscle. In Cat + free medium with 0.1 mM EGTA, the carhachol-induced contractions were significantly increased by adding of Ca2+ (10-4 - 3x10-3M) dose dependently (p<0.05). This increase was found to he as 69,75±5.52 % and 42.89±4.13 % in the presence of 10-6M and 10-5M verapamil, respectively. In the other part of study carried out using normal solution, the carhachol (10-6M) induced contractions were inhibited by cumulative addition (10-9 - 10-4M) of atropin. amitriptyline and maprotiline. Results suggest that, intracellular calcium was used as well as extracellular calcium for contractions due to carhachol in this tissue. In addition, the antagonists significantly inhibited the contractions induced with carhachol and according to IC50 these antagonists were following order of potency atropin > amitriptyline > maprotiline (p<0.05).