Comparison of anterior hypothalamic and preoptic thermosensitive neurons in vitro.

Single-unit studies of neurons in anterior hypothalamic (AH) slices and medial preoptic (MPO) slices in vitro isolated from each other revealed that thermosensitive neurons found in both slices have essentially the same properties. Quantitative differences observed were that AH neurons had lower firing rate at neutral temperature and AH warm-sensitive neurons had higher threshold temperature above which the neurons were thermosensitive. Some of AH and MPO warm-sensitive neurons tested did not lose their thermosensitivity in Ca2+-deficient solution. Thus, the primary warm-sensitive neurons having inherent thermosensitivity exist in the AH as well as MPO.