Search results for " AT1 receptors"
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Angiotensin II positively modulates the spontaneous contractile activity of mouse and human colon via activation of AT1 receptors.
2012
Objective: Angiotensin II (Ang II) is a potent smooth muscle contractile neurohumoral agonist but has not been much investigated with regard to gastrointestinal motor activity. Ang II effects are mediated by specific receptors, the Ang II type 1 (AT1) and the Ang II type 2 (AT2) receptors, which are well expressed in the gut. In this study we evaluated the effects of Ang II on the contractile activity of longitudinal muscle from mouse and human colon and we analysed the subtype(s) of receptors involved in the observed effects. Methods: Mechanical responses to Ang II, in the absence or in the presence of different drugs, were assessed in vitro in colonic longitudinal muscle from mice and hum…
Angiotensin II contractile effects in mouse colon: role for pre- and post-junctional AT1A receptors
2013
Aim This study investigates whether a local renin–angiotensin system (RAS) exists in mouse colon and whether angiotensin II (Ang II) may play a role in the regulation of the contractile activity. Methods Isometric recordings were performed in vitro on the longitudinal muscle of mouse proximal and distal colon. Transcripts encoding for RAS components were investigated by RT-PCR. Results Ang II caused, in both preparations, a concentration-dependent contractile effect, antagonized by losartan, AT1 receptor antagonist, but not by PD123319, AT2 receptor antagonist. The combination of losartan plus PD123319 caused no change on the Ang II-induced contraction than losartan alone. Tetrodotoxin, neu…