Identification of serotonin from rabbit upper stomach as a stimulant of in vitro gallbladder contraction.
Using an in vitro rabbit gallbladder bioassay, the distribution and identification of bioactive substances in rabbit gastrointestinal tract were investigated. Comparison of the bioactivities of tissue extracts before and after cholecystokinin was removed by affinity chromatography demonstrated that the distributions of cholecystokinin and non-cholecystokinin substances were different. While cholecystokinin bioactivity per g of tissue was highest in the duodenum, non-cholecystokinin bioactivity was greatest in the upper stomach. The biochemical properties of the non-cholecystokinin substance in the upper stomach could not be distinguished from those of serotonin. These included molecular weights of 176, identical ultraviolet spectra, similar nuclear magnetic resonance spectra, and co-chromatography in HPLC. By weight, serotonin had 1/6th of the bioactivity of cholecystokinin octapeptide. We conclude that the principal gallbladder-contracting substance in rabbit upper stomach is serotonin.
Cox
K L
KL
Department of Pediatrics, University of California, Davis.
Rosenquist
G L
GL
Iwahashi
C K
CK
Benisek
W F
WF
Reeve
J R
JR
Shively
J E
JE
Lee
T
T
Huebner
V D
VD
D000818:Animals; D002766:Cholecystokinin / Q000032:analysis / Q000502:physiology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005704:Gallbladder / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011817:Rabbits; D012701:Serotonin / Q000032:analysis* / Q000494:pharmacology / Q000502:physiology; D013056:Spectrophotometry, Ultraviolet; D013270:Stomach / Q000502:physiology*
D012701:Serotonin; D002766:Cholecystokinin