HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/4/R742    most recent 00041.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Cardin, S. Articles by Cherrington, A. D. Search for Related Content PubMed PubMed Citation Articles by Cardin, S. Articles by Cherrington, A. D.

APPETITE, OBESITY, DIGESTION, AND METABOLISM

Vagal cooling and concomitant portal norepinephrine infusion do not reduce net hepatic glucose uptake in conscious dogs

Department of Molecular Physiology and Biophysics and Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615

Submitted 20 January 2004 ; accepted in final form 25 May 2004

We examined the role of efferent neural signaling in regulation of net hepatic glucose uptake (NHGU) in two groups of conscious dogs with hollow perfusable coils around their vagus nerves, using tracer and arteriovenous difference techniques. Somatostatin, intraportal insulin and glucagon at fourfold basal and basal rates, and intraportal glucose at 3.8 mg·kg^–1·min^–1 were infused continuously. From 0 to 90 min [period 1 (P1)], the coils were perfused with a 37°C solution. During period 2 [P2; 90–150 min in group 1 (n = 3); 90–180 min in group 2 (n = 6)], the coils were perfused with –15°C solution to eliminate vagal signaling, and the coils were subsequently perfused with 37°C solution during period 3 (P3). In addition, group 2 received an intraportal infusion of norepinephrine at 16 ng·kg^–1·min^–1 during P2. The effectiveness of vagal suppression was demonstrated by the increase in heart rate during P2 (111 ± 17, 167 ± 16, and 105 ± 13 beats/min in group 1 and 71 ± 6, 200 ± 11, and 76 ± 6 beats/min in group 2 during P1–P3, respectively) and by prolapse of the third eyelid during P2. Arterial plasma glucose, insulin, and glucagon concentrations; hepatic blood flow; and hepatic glucose load did not change significantly during P1–P3. NHGU during P1-P3 was 2.7 ± 0.4, 4.1 ± 0.6, and 4.0 ± 1.2 mg·kg^–1·min^–1 in group 1 and 5.0 ± 0.9, 5.6 ± 0.7, and 6.1 ± 0.9 mg·kg^–1·min^–1 in group 2 (not significant among periods). Interruption of vagal signaling with or without intraportal infusion of norepinephrine to augment sympathetic tone did not suppress NHGU during portal glucose delivery, suggesting the portal signal stimulates NHGU independently of vagal efferent flow.

vagus nerve; efferent neural transmission