Calcitonin gene-related peptide: an inhibitor of bullfrog (Rana catesbeiana) gallbladder contraction in vitro.
The presence of a calcitonin gene-related peptide (CGRP)-like material was demonstrated in the gallbladder of the bullfrog, Rana catesbeiana, using immunocytochemistry and confirmed by radioimmunoassay. An intense immunocytochemical reaction was observed in nerves located in the smooth muscle layers and associated with blood vessels. No immunoreactive nerve fibers were associated with ganglia, nor were immunoreactive cell bodies observed. Radioimmunoassay showed that 25.03 +/- 2.5 pmol/g tissue of CGRP-like material was present. In vitro tension studies using gallbladder strips showed that CGRP exerted an inhibitory effect on both acetylcholine- and cholecystokinin octapeptide-induced tension but had no effect on KCl-, norepinephrine-, or cerulein-induced tension. CGRP may act directly on the gallbladder smooth muscle to inhibit contraction.
Kline
L W
LW
Department of Oral Biology, University of Alberta, Edmonton, Canada.
Kaneko
T
T
Chiu
K W
KW
Pang
P K
PK
D000109:Acetylcholine / Q000037:antagonists & inhibitors; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis / Q000494:pharmacology*; D002108:Ceruletide / Q000494:pharmacology; D002766:Cholecystokinin / Q000037:antagonists & inhibitors; D005704:Gallbladder / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D009412:Nerve Fibers / Q000737:chemistry; D009638:Norepinephrine / Q000494:pharmacology; D011863:Radioimmunoassay; D011892:Rana catesbeiana / Q000378:metabolism*
D002108:Ceruletide; D002766:Cholecystokinin; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine; D009638:Norepinephrine