Eating-related increase of dopamine concentration in the lha with
oro-nasal stimulation.
Yang, Zhong-Jin, Masato Koseki, Michael M. Meguid, and Alessandro
Laviano.
Surgical Metabolism and Nutrition Laboratory, Neuroscience Program,
Department of Surgery, University Hospital, SUNY Health Science
Center, Syracuse, NY 13210
APStracts 2:0250R, 1995.
Previously, we showed that eating was associated with an increase in
lateral hypothalamic-dopamine (LHA-DA) which returns to previous
level when eating stops. We therefore hypothesize that LHA-DA release
may be primarily contributed to by oro-nasal stimulation. To test our
hypothesis, microdialysis was used to compare LHA-DA release during
oral and intragastric feeding. A gastrostomy tube was inserted in 12
rats. After recovery from surgery, in vivo microdialysis was per
formed. Six rats were allowed to drink a liquid diet, while in
another 6 rats the same liquid diet was infused at paired doses
(volume= 4.8+0.6 ml; time= 5-10 min) through the gastrostomy tube
into the stomach. Oral feeding increased baseline LHA-DA from
10.6+0.2 pg/10 _l dialysate to 14.0+0.8 pg/10 _l (p<0.01) within
20 min. No significant change in measured LHA-DA occurred during
intragastric feeding [baseline: 10.5+0.3 pg/10 _l to post
-intragastric: 10.2+0.3 pg/10 _l (p<0.01 vs. oral feeding)],
indicating that LHA-DA release occurs with oro-nasal stimulation.
Received 6 January 1995; accepted in final form 17 August 1995.
APS Manuscript Number R12-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.