Effects of vasoactive intestinal polypeptide microinjected into the nucleus tractus solitarius on jejunal glucose absorption in rats.
It has been shown that vasoactive intestinal polypeptide (VIP) injected into the nucleus tractus solitarius and into the dorsal motor nucleus of the vagus inhibits alanine absorption across the jejunum. The aim of the present study was to investigate the effects of VIP injection into the nucleus tractus solitarius on jejunal absorption of glucose in the rat. Forty Wistar rats were submitted to midline laparotomy to expose and isolate 20 cm of jejunal loop and to perform a subdiaphragmatic troncular vagotomy. Saline or VIP (10 pg 100 nl(-1)) was injected into the rostral nucleus tractus solitarius using a stereotaxic instrument. Tyrode solution, pH 8, containing twice glucose, sodium, and potassium concentrations was infused (0.5 ml min(-1)) into the jejunal loop. Samples were taken at 10-min intervals during the 40-min experiment. Injection of VIP into the nucleus tractus solitarius associated with vagotomy resulted in inhibition of jejunal glucose absorption by VIP alone at 10 and 40 min after perfusion (2.75+/-0.19 vs. 3.53+/-0.29 mg). The vagal outflow tract maintained jejunal glucose absorption even when VIP was microinjected into the nucleus tractus solitarius.
Borges
Elizabeth L
EL
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 CEP 31270-010, Belo Horizonte, MG, Brazil. borgesel@icb.ufmg.br
Machado
Alvaro D C V
AD
Haibara
Andréa S
AS
Petroianu
Andy
A
D000818:Animals; D005947:Glucose / Q000378:metabolism*; D007276:Injections, Intraventricular; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology; D007583:Jejunum / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008845:Microinjections; D051381:Rats; D017208:Rats, Wistar; D017552:Solitary Nucleus / Q000187:drug effects* / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage*
D014660:Vasoactive Intestinal Peptide; D005947:Glucose