THERMOSENSITIVITY - AN INTRINSIC PROPERTY OF HYPOTHALAMIC NEURONS

1. Marked temperature dependence of impulse activity is a property of mammalian neurons which are mainly localized in the hypothalamus and a djoining brain regions. 2. Data is presented on the similarity of ther mal behaviour of neurons in vivo and in vitro. It follows from the evi dence on the synaptic blockade, postnatal development, and intracellul ar recordings that inherent thermosensitivity is a property primarily of warm-sensitive hypothalamic neurons. 3. The Na+/K+ pump does not un derlie hypothalamic neuron thermosensitivity. Warm-sensitive units pos sess highly thermosensitive non-inactivating inward sodium current. 4. Data is presented on thermo-induced membrane structural rearrangement s based on changes in the physical state of lipids, changes in protein conformation and membrane skeleton activity. A hypothesis of the rela tion of threshold temperature responses of warm sensitive hypothalamic neurons with these membrane phenomena, as well as alternative hypothe ses, are viewed.