Influence of baclofen on temperature-sensitive neurons in chick hypothalamus

The effects of the GABA(B)-receptor agonist baclofen on neuronal tonic activity (firing rate) and temperature sensitivity (temperature coefficient, TC) of neurons in the preoptic area/anterior hypothalamus (PO/AH) have been examined in chick brain slices, using extracellular recordings. The tonic activity of both warm-sensitive and cold-sensitive neurons, as well as temperature-insensitive neurons, was significantly inhibited by superfusion with baclofen (1 microM). It is clearly evident from the present study that there was an increasing trend in warm-sensitive neurons and a significant (p<0.05) increase in TC of cold-sensitive neurons. Relatively high percentage (31.5%) of chick PO/AH neurons was determined as cold sensitive by present investigation. Particularly, GABA(B) mechanisms modify temperature sensitivity of the PO/AH neurons and thus modulation of temperature sensitivity in PO/AH is involved in the control of body temperature.