Yukio Hara, Akihito Chugun, Keisuke Futamura, Takeshi Nishino and Hiroshi
Department of Veterinary Pharmacology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Higashi 23 ban-cho 35 - 1, Towada, Aomori 034 - 8628, Japan
Abstract: Influences of diazepam, a benzodiazepine derivative, on the contractile response to calcium in skinned trabecular fibers of guinea pig heart were examined. Diazepam (100 ÊM) enhanced the contractile response of the skinned fiber to calcium and shifted the concentration-response curve to the left. The pCa50 values were 6.07}0.03 and 6.28}0.03 (P<0.05) in the absence and presence of diazepam, respectively. This result suggests that diazepam increases calcium sensitivity of contractile proteins in heart muscles.
Keywords: Calcium sensitivity, Diazepam, Skinned cardiac muscle