Physiological and anatomical evidence for the existence of nerve tracts connecting the hypothalamus with spinal sympathetic centres

TLDR

In animals under chloroform anaesthesia, the heart is prone to ventricular extrasystoles. The authors showed that these extrasystoles and ensuing fibrillation can be elicited by sympathetic stimulation, but are abolished by removal of sympathetic nerves and adrenal glands, with adrenaline injection reinstating the phenomenon.

Abstract

Levy* (1) in a series of papers has shown that in animals (chiefly cats) under chloroform anaesthesia the heart is particularly liable to show ventricular extrasystoles. These irregularities are often followed by fibrillation. He found that if the irregularity was not present it could be elicited easily by any form of sympathetic stimulation, either direct, reflexly, or through drugs, such as nicotine or adrenaline. Furthermore, removal of the sympathetic nerve supply to the heart along with removal of the adrenal glands rendered the heart immune to this phenomenon. After this procedure reflex stimulation of the sympathetic nervous system was ineffective, but injection of adrenaline readily reproduced the original series of events.