Effects of Intracarotid Injection of Hypertonic Saline on Spinal Reflex Excitability

Abstract

DURING the past few years¹ we have been able to demonstrate that increasing the extracellular osmotic pressure by subcutaneous injection of hypertonic saline not only induces thirst and drinking in the rat, which has been extensively studied by others², but also produces an increase in the responsiveness of the animal and a relatively intense facilitation of previously learned thirst-associated simple motor acts³ like running through an enclosed alley. The purpose of the present series of experiments was to measure this facilitatory effect in terms of an electrophysiological change in the final common path involved in the expression of this behaviour.