THE RELATION BETWEEN SKIN TEMPERATURE AND THE EFFECT OF MORPHINE UPON THE RESPONSE TO THERMAL STIMULI IN THE ALBINO RAT AND THE DOG

¹ Merck Institute for Therapeutic Research, Rahway, New Jersey

Morphine produces a rise in rectal and skin temperatures in rats, but a decrease in dogs.

The relationship of skin temperature to the threshold of reaction to thermal stimuli in dogs is such that a drop of 1°C. in skin temperature raises the threshold by 2 watts with the equipment used in this laboratory. The lowering of skin temperatures in the dog accounts for much of the rise in threshold observed after morphine in this species.

In rats, on the other hand, a rise in threshold after morphine is due entirely to an increase in the temperature of reaction; indeed, an elevation in threshold in this species occurs in spite of an elevation in skin temperature.