GABA release in the zona incerta of the sheep in response to the sight and ingestion of food and salt.
In order to establish which neurotransmitters may influence the activity of zona incerta neurones in the sheep which respond selectively to the sight or ingestion of food, we have measured the release of amino acid and monoamine neurotransmitters from this region using microdialysis sampling. Co-ordinates for the placement of microdialysis probes in regions of the zona incerta where cells respond to the sight or ingestion of food were first established by making single-unit extracellular recordings. When animals were food-deprived results showed that release of gamma-aminobutyric acid (GABA) was increased in response to the sight and ingestion of food but not of aspartate, glutamate, taurine, noradrenaline, dopamine or serotonin. This release of GABA was absent when the animals were shown non-food objects or saw or ingested salt solutions. When the same animals were physiologically sodium-depleted GABA release was evoked by the sight and ingestion of salt solutions and release following the sight and ingestion of food was significantly reduced. These results provide further evidence that GABA is an important neurotransmitter in neural circuits controlling the regulation of food intake.
Kendrick
K M
KM
A.F.R.C. Institute of Animal Physiology and Genetics Research, Cambridge Research Station, Babraham, U.K.
Hinton
M R
MR
Baldwin
B A
BA
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000502:physiology*; D004027:Diencephalon / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D004435:Eating / Q000502:physiology*; D005502:Food; D005508:Food Deprivation; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D010487:Periaqueductal Gray / Q000502:physiology*; D010812:Physical Stimulation; D012756:Sheep; D012965:Sodium Chloride; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D012965:Sodium Chloride; D005680:gamma-Aminobutyric Acid; D004298:Dopamine; D009638:Norepinephrine