Inhibitory effects on intake of cholecystokinin-8 and cholecystokinin-33 in rats with hepatic proper or common hepatic branch vagal innervation

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2005-08, Vol.289 (2), p.R456-R462
• Main Authors: Eisen, S, Phillips, R. J, Geary, N, Baronowsky, E. A, Powley, T. L, Smith, G. P
• Format: Article
• Language: English
• Subjects: Afferent Pathways - physiology; Animals; Appetite Depressants - administration & dosage; Appetite Depressants - pharmacology; Cholecystokinin - administration & dosage; Cholecystokinin - pharmacology; Eating - drug effects; Injections, Intraperitoneal; Liver - innervation; Male; Rats; Rats, Sprague-Dawley; Satiety Response; Sincalide - administration & dosage; Sincalide - pharmacology; Triticum aestivum; Vagus Nerve - drug effects; Vagus Nerve - physiology
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00062.2005

1 Department of Psychiatry, Weill Medical College of Cornell University and New York-Presbyterian Hospital, Westchester Division, White Plains, New York; and 2 Department of Psychological Sciences, Purdue University, West Lafayette, Indiana Submitted 1 February 2005 ; accepted in final form 30 March 2005 The relative potencies of cholecystokinin (CCK)-8 and CCK-33 for decreasing meal size depend on the route of administration. Inhibitory potencies are equal after intraperitoneal administration, but CCK-33 is significantly more potent after intraportal administration. This suggests that CCK-33 is a more effective stimulant of hepatic afferent vagal nerves than is CCK-8. To investigate this possibility, we administered both peptides intraperitoneally in rats with abdominal vagotomies that spared only the hepatic proper vagal nerves (H) and in rats with abdominal vagotomies that spared the common hepatic branch that contains the fibers of the hepatic proper and gastroduodenal nerves (HGD). The vagal afferent innervation in H and HGD rats was verified with a wheat germ agglutinin-horseradish tracer strategy. Intraperitoneal administration of CCK-33 decreased 30-min intake of 10% sucrose in H rats as much as in sham rats, but CCK-8 decreased intake significantly less in H rats than in sham rats. The larger inhibitory effect of CCK-33 than of CCK-8 in H rats is consistent with the hypothesis that CCK-33 is a more effective stimulant of the hepatic proper vagal afferent nerves than CCK-8. In contrast to the results in H rats, the inhibitory potencies of both peptides were significantly and equivalently reduced in HGD rats compared with sham rats. This suggests that there is an inhibitory interaction between the stimulation of the gastroduodenal and hepatic proper afferent fibers by CCK-33. food intake; meal size; satiety; postingestive negative feedback; gastroduodenal branch of abdominal vagus Address for reprint requests and other correspondence: G. P. Smith, New York-Presbyterian Hospital, Westchester Division, 21 Bloomingdale Rd., White Plains, NY 10605 (e-mail: gpsmith{at}med.cornell.edu )