Bufokinin: immunoreactivity, receptor localization and actions in toad intestine and mesenteric circulation.
In this study, we have mapped the immunoreactivity and the binding sites for bufokinin, a tachykinin peptide from the toad intestine. Dense bufokinin-immunoreactive fibers were present at the myenteric plexus, but no cell bodies were stained, suggesting an extrinsic origin. Bufokinin nerve fibers were also associated with submucosal blood vessels and mesenteric arteries. Autoradiographic binding sites for [(125)I]Bolton-Hunter-bufokinin were densely localized over the intestinal circular and longitudinal muscle, submucosal blood vessels and the endothelium of mesenteric arteries. Mesenteric veins had minimal immunoreactivity and binding sites. In the anesthetized toad, topical application of bufokinin onto the mesentery caused a 2.7-fold increase in arterial blood flow, observed using intravital microscopy. This study supports a role for bufokinin as an endogenous spasmogen and hemodynamic regulator in the toad intestine.
Liu
L
L
School of Physiology and Pharmacology, University of New South Wales, NSW 2052, Sydney, Australia.
Shang
F
F
Perry
M A
MA
Comis
A
A
Burcher
E
E
D000818:Animals; D001665:Binding Sites; D002025:Bufonidae; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D007422:Intestines / Q000737:chemistry*; D008638:Mesenteric Arteries / Q000737:chemistry / Q000187:drug effects; D008642:Mesenteric Veins / Q000737:chemistry; D008833:Microcirculation; D018039:Receptors, Tachykinin / Q000302:isolation & purification*; D013152:Splanchnic Circulation; D013388:Succinimides; D015320:Tachykinins / Q000302:isolation & purification* / Q000494:pharmacology; D014018:Tissue Distribution
D002352:Carrier Proteins; D036341:Intercellular Signaling Peptides and Proteins; D018039:Receptors, Tachykinin; D013388:Succinimides; D015320:Tachykinins; C112071:bufokinin; C022581:Bolton-Hunter reagent