The Journal of physiology
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The Journal of physiology · Apr 1973
The hypothermic effect of tetrodotoxin in the unanaesthetized cat.
1. The hypothermic effect on unanaesthetized cats of tetrodotoxin injected I. V. or into the lateral cerebral ventricle was examined.2. ⋯ Activation of heat-loss mechanisms, and the absence of compensatory shivering during development of hypothermia after tetrodotoxin administration, plus lowering of T(b) by tetrodotoxin at T(a) above as well as below the thermoneutral temperature, indicate that lowering of the thermoregulatory set-point is the mechanism by which centrally or peripherally administered tetrodotoxin lowers T(b). Further evidence for set-point lowering after intraventricular administration of tetrodotoxin is provided by persistence of the ability to regulate against both heat and cold stresses during hypothermia. The possibility that the decrease in set-point could be due to the well known action of tetrodotoxin to block transient increases in membrane sodium ion conductance is discussed in terms of a recent hypothesis regarding ionic control of the thermoregulatory set-point.