Eating-related increase of dopamine concentration in the LHA with oronasal stimulation.
Previously, we showed that eating was associated with an increase in lateral hypothalamic area dopamine (LHA-DA) release, which returns to previous level when eating stops. We therefore hypothesize that LHA-DA release may be primarily contributed to by oronasal 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 performed. Six rats were allowed to drink a liquid diet, whereas in another six 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 to 14.0 +/- 0.8 pg/10 microliters dialysate (P < 0.01) within 20 min. No significant change in measured LHA-DA occurred during intragastric feeding [baseline: 10.5 +/- 0.3 pg/10 microliters; postintragastric: 10.2 +/- 0.3 pg/10 microliters (P < 0.01 vs. oral feeding)], indicating that LHA-DA release occurs with oronasal stimulation.
Yang
Z J
ZJ
Department of Surgery University Hospital, State University of New York Health Science Center, Syracuse 13210, USA.
Koseki
M
M
Meguid
M M
MM
Laviano
A
A
D000284:Administration, Oral; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D004435:Eating / Q000502:physiology*; D004750:Enteral Nutrition; D007026:Hypothalamic Area, Lateral / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D011916:Rats, Inbred F344
D004298:Dopamine