Effects on temperature of monoamines injected into the cerebral ventricles of anaesthetized dogs.

1. In dogs anaesthetized with pentobarbitone sodium an injection of adrenaline or noradrenaline into the cerebral ventricles through a cannula implanted into the left lateral ventricle caused a fall in rectal temperature as a result of cessation of shivering, loss of muscle tone, and skin vasodilatation. 5-Hydroxytryptamine (5-HT) similarly applied caused shivering and a rise in rectal temperature.2. The hypothalamus of the dog thus appears to react to the three monoamines in the same way as in the cat, and not as in the rabbit and sheep.