In atrial and ventricular cells from hearts of hatched chicks, acetylcholine reduced the overshoot and the duration of action potentials recorded in normal Tyrode's solution (5.4 ITIM K). This effect of acetylcholine is attributed to inhibition of the slow inward current-dependent portion of the action potential because acetylcholine reduced the overshoot, rate of rise, and duration of the Ca/N...

Previous experiments have demonstrated that the rat dorsomedial striatum is one brain area that plays a crucial role in learning when conditions require a shift in strategies. Further evidence indicates that muscarinic cholinergic receptors in this brain area support adaptations in behavioral responses. Unknown is whether specific muscarinic receptor subtypes in the dorsomedial striatum contrib...

Crocin, a component of saffron, showed hypotensive which is perhaps due to vascular smooth muscle relaxant effect. The relaxant effects of saffron on tracheal smooth muscle also could be due to its constituent, crocin. In the present study, the relaxant effects of crocin and its possible mechanisms on rat tracheal smooth muscle were investigated. The relaxant effects of three cumulative concent...

Muscarinic receptors play a major role in gallbladder function, although the muscarinic receptor(s) mediating smooth muscle contractility is unclear. This study compared smooth muscle contractile responses to carbamylcholine (10(-7)-10(-3) M) in isolated gallbladder from wild-type and M(2), M(3), and M(4) receptor knockout mice. Carbamylcholine-induced contraction in gallbladder was associated ...

OBJECTIVES Carbachol-induced contraction of the rat colon is impaired in rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis. The main objective of this study was to examine the effect of colitis on the expression and function of muscarinic (M) receptor subtypes in the rat colon. MATERIALS AND METHODS Rats (n = 80) were treated with TNBS and used 5 days later for measurement of con...