Opposite excitatory and inhibitory effects of central administration of glucagon and of insulin upon the sympathetic cervical and adrenal nerve activities in the rat.

The central effects of pancreatic glucagon and insulin given intracerebroventriculary (i.c.v.) upon sympathetic activity in the cervical trunk and adrenal nerve were examined in Wistar Kyoto rats. Glucagon i.c.v. administration led to an increase in sympathetic nerve activity in both nerves. Insulin injected into lateral ventricle caused opposite to glucagon inhibitory influence on sympathetic discharge in the cervical trunk and adrenal nerve. This two different central effects of glucagon and insulin on sympatho-adrenal system may contribute to glycemia homesthasis.