Regulation of the descending relaxation phase of intestinal peristalsis by PACAP

Mediators of Nonadrenergic, Noncholinergic Relaxation in Sprague Dawley Rat Intestine: Comparison with the Mediators of Other Strains.

“…The present results indicate that VIP participates NANC relaxation only in the distal colon of Wistar and Wistar-ST, but not Sprague Dawley rats. It has been suggested that PACAP induces the relaxation via opening of apamin-sensitive K + channels in the colon of rats [8] and the tenia coli of guinea pigs [12] and mediated i.j.ps via opening of the channels in the caecum of guinea pigs [17]. We also suggested that PACAP mediates about half NANC relaxation in the distal colon of Wistar-ST rats via opening of apamin-sensitive K + channels [15,25].…”

“…Pituitary adenylate cyclase activating peptide (PACAP) was also suggested to mediate NANC relaxation in some regions: lower oesophageal sphincter of cats and humans [20], stomach of guinea pigs [14], and colon of guinea pigs [12] and rats [8,15]. We suggested that VIP and PACAP mediate NANC relaxation of longitudinal muscle of the distal colon of Wistar-ST rats via opening of charybdotoxin-and apamin-sensitive K + channels, respectively [15,25].…”

VIP‐ and PACAP‐mediated nonadrenergic, noncholinergic inhibition in longitudinal muscle of rat distal colon: involvement of activation of charybdotoxin‐ and apamin‐sensitive K+ channels

“…On the other hand, studies on circular muscle of the rat distal colon showed an important role of nitric oxide in NANC inhibition (Middleton et al, 1993). It was also shown, in circular muscle of the rat middle or distal colon, that VIP and PACAP released from inhibitory neurones produced nitric oxide in smooth muscle cells which in turn resulted in relaxant responses (Grider, 1993;Grider et al, 1994). It seems that NANC inhibitory mediators in the rat distal colon are different between longitudinal and circular muscle, in spite of a small restricted intestinal area.…”

Pituitary Adenylate Cyclase-Activating Polypeptide and Its Receptors: 20 Years after the Discovery

“…PACAP also exerts a relaxant effect on intestinal smooth muscles from rat (Mungan et al, 1992a;Schwörer et al, 1992;Katsoulis et al, 1993b;Grider et al, 1994;Ekblad and Sundler, 1997;Olsson and Holmgren, 2000), guinea pig (Mungan et al, 1992a;Schwörer et al, 1992;Katsoulis et al, 1993b;Grider et al, 1994;Ekblad and Sundler, 1997;Olsson and Holmgren, 2000) and Atlantic cod, Gadus morhua (Mungan et al, 1992a;Schwörer et al, 1992;Katsoulis et al, 1993b;Grider et al, 1994;Ekblad and Sundler, 1997;Olsson and Holmgren, 2000), thus reducing the motility of the bowel (Lä uff et al, 1999). The mechanism by which PACAP induces muscle relaxation along the gastrointestinal tract has been extensively studied.…”