Hypothalamic warm-sensitive neurons possess a tetrodotoxin-sensitive sodium channel with a high Q10.
We have investigated the ionic current responses to temperature of dissociated cells from the preoptic and anterior hypothalamus (PO/AH) of rat, using the 'whole-cell' configuration. The majority of the recorded neurons showed a linear increase in a non-inactivating inward current during warming (30-40 degrees C), and the Q10 was about 2. However, about 24% of PO/AH neurons were markedly sensitive to warming and the increase in non-inactivating inward current to a rise in temperature in the hyperthermic range (35-40 degrees C) had a high Q10 (4.3-7.0). This increase in current in the hyperthermic range was reversibly blocked by tetrodotoxin (TTX). The inward current in neurons with a Q10 of 2 was not affected by TTX. The results show that some neurons in the PO/AH possess a non-inactivating sodium channel that is highly temperature-sensitive in the hyperthermic range. These neurons are presumably the 'primary' warm-sensitive neurons.
Kiyohara
T
T
Department of Physiology, Saga Medical School, Japan.
Hirata
M
M
Hori
T
T
Akaike
N
N
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D006358:Hot Temperature; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology*
D015222:Sodium Channels; D013779:Tetrodotoxin