Pharmacological characterization of the contractile responses to angiotensin analogues in guinea‐pig isolated longitudinal muscle of small intestine

Angiotensin II type II receptors and colonic dysmotility in 2,4‐dinitrofluorobenzenesulfonic acid‐induced colitis in rats

“…All the RAS components have been identified in the animal and human intestine and they are suggested to be involved in modulation of GI epithelial transport processes and motor activity . Angiotensin II induces contractile responses in intestinal muscle, via activation of neural AT 1 receptors, modulating release of ACh or substance P, and/or AT 1 receptors located postjunctionally at smooth muscle level . Although the expression of AT 2 receptors has been reported in the GI wall, they seem to be uncoupled to contractile mechanisms in physiological condition.…”

The Effects of Some Neuropeptides on Motor Activity of Smooth Muscle Organs in Abdominal and Pelvic Cavities

“…Most of the effects of Ang II concerning the smooth muscle contractile activity of GIT are associated with AT1 receptors (Fändriks, 2010;Fan et al, 2002;Hawcock & Barnes, 1993;Rattan et al, 2003). AT2 receptors are also described in GIT (Fändriks, 2010;Fan et al, 2002;Hawcock & Barnes, 1993;Ewert et al, 2003;Leung et al, 1993;De Godoy et al, 2002).…”

“…AT2 receptors are also described in GIT (Fändriks, 2010;Fan et al, 2002;Hawcock & Barnes, 1993;Ewert et al, 2003;Leung et al, 1993;De Godoy et al, 2002). Although different signaling pathways have been assumed, for example activation of various phosphatases, cGMP -NO system etc.…”

“…It had been demonstrated that only AT1 receptors are relevant for the maximum response in ANG-induced contractions (Hawcock & Barnes, 1993;Fändriks, 2010;Fan et al, 2002;Rattan et al, 2003;Ewert et al, 2006;Fändriks, 2010). Despite the existing assumptions that stimulation of AT2 receptors may have the opposite effect than that of AT1 (Gallinat et al, 2000), the role of AT2 receptors for the relaxation phase of the SMC in GIT is not examined.…”

“…Dosedependent curves, which are commonly used as a method for studying the provoked smooth muscle contractions (Fändriks, 2010;Fan et al, 2002;Hawcock & Barnes, 1993;Leung et al, 1993;Park et al, 1973), could give information about the effective doses and maximal responses, but not a data for other important characteristics of the smooth muscle contractions. The different phases of the contraction in the various segments of the GIT, were not clarified and analyzed by application of a time-parameter analysis, as it was made in the study of the skeletal muscle contraction (Raikova & Aladjov, 2004).…”