Electrical field stimulation (EFS) induces frequency-dependent contractions of the longitudinal muscle of isolated quail rectum which were sensitive to tetrodotoxin. The aim of the present study was to investigate whether purinergic neurons are implicated in the response to nerve stimulation. arabic 18 English 103
M. Draid(4-2007)

The relationship between ATP-induced membrane potential and contraction was inestigated in the smooth muscle of chicken anterior mesenteric artery using micro-electrode and tension recording techniques respectively. Application of ATP to en-dothelium-denuded arterial preparations developed concentration-dependent, slow depolarization which started only at concentrations not less than 10 μM. On the other hand the tension recording experiment revealed that ATP produced concentration dependent contractions, which were evident at concentrations lower than those evoked depolarizing response to ATP (as lower 100 nM). Both depolarizing & contracting responses were abolished by the P2X receptor blocker, PPADS (50 μM) but not by P2Y receptor blocker CBF3GA (100 μM), indicating that the excitatory responses of ATP were mediated via activation of P2X receptor. These findings suggest that ATP-mediated contraction is not dependent on membrane depolarization only, at least at low concentrations in the first order branches of chicken anterior mesenteric artery. arabic 21 English 153
Marwan Draid(7-2012)

The neurotransmitter(s) that generate the inhibitory junctional potential (IJP) in the circular muscle of hamster distal colon and their mechanisms have not been elucidated. The aim of the present study, therefore, was to determine the contributing roles of the non-adrenergic, non-cholinergic (NANC) inhibitory transmitter(s) including nitric oxide (NO), adenosine 5′-triphosphate (ATP) and vasoactive intestinal polypeptide (VIP) in the generation of IJP in the hamster distal colon. For this purpose, the effects of the corresponding blockers of these putative NANC inhibitory mediators have been investigated using microelectrode technique. arabic 8 English 62
M. Draid(12-2006)