Response of thermoresponsive neurons of rat's hypothalamus during intracarotid infusion of prostaglandin E 2

Abstract

We investigated the effect of intracarotid infusion of prostaglandin E 2 (PGE 2) on the single-unit activity of neurons in the preoptic and anterior hypothalamic (PO/AH) region. A total of 35 neurons in the PO/AH region were examined: 10 were warm-responsive neurons, 6 were cold-responsive neurons, and 19 were thermally insensitive neurons. In the warm-responsive neurons, the activities of 4 neurons were facilitated, while 3 neurons were inhibited and 3 neurons were not affected after intracarotid infusion of PGE 2. In the cold-responsive neurons, the activities of 2 neurons were facilitated and 4 neurons were not affected by PGE 2 infusion. Furthermore, 15 out of 19 thermally insensitive neurons were not affected by PGE 2 infusion. These results suggest that thermoresponsive neurons of the PO/AH region respond well to intracarotid infusion of PGE 2, compared with thermally insensitive neurons. However, the direction of neuronal response induced by intracarotid infusion of PGE 2 could not be generally categorized based on the thermoresponsiveness of individual neurons.