Effects of calcium and potassium injected into the cerebral ventricles of the cat

Abstract

In previous experiments (Feldberg & Sherwood, 1954a, b, 1955 injections of a number of drugs into the lateral cerebral ventricles of the unanaesthetized cat and the ensuing behavioural changes have been described. The present experiments are a continuation of this work and deal with the effects of intraventricular injections of calcium and potassium. These cations are known to exert powerful central depressant and excitatory effects respectively when given systemically or applied locally, but only a few experiments have so far been conducted in which the effects have been studied when these ions are introduced into the cerebral ventricles or into the great cisterna.The effects on injection of calcium and potassium into the cerebral ventricles of cats were studied by Marinesco, Sager & Kreindler (1929). The salts were injected under light ether anaesthesia and the effects observed as the anaesthetic wore off. The injection of 1 mg calcium chloride caused, after a latency of about 1 hr, sleep which lasted for several hours. The injection of 1 mg potassium chloride resulted in clonic contractions which lasted for 20 min; afterwards the cats were unable to walk and were very excited, and about 2 hr after the injection they fell asleep for several hours, whilst respiration was accelerated and the body temperature raised. Stern (1945) pointed out that an increase of the potassium:calcium ratio in the cerebrospinal fluid raised the tonus of the sympathetic nervous system and influenced the general state of excitation of the central nervous system. The intraventricular injection of a few milligrams of potassium into humans resulted in augmentation of cardiac activity, increased muscle tone and general excitability. Stern advocated the injection of a mixture of potassium dihydrogen and dipotassium hydrogen phosphates (2-7 ml. of a solution containing 6-5 mg potassium/ml.) for the treatment of shock. The mixture was 'introduced suboccipitally to the vegetative centres' in many war cases, and the result was satisfactory. In experiments on animals in a condition of shock,

Seizure-like afterdischarges simulated in a model neuron

“…Several decades ago Feldberg and Sherwood (1957) and Zuckermann and Glaser (1968) have shown that direct application of high K + solution to the brain of experimental animals can cause epileptiform convulsions. Later Korn et al (1987) reported that raising K + concentration in the organ bath induced seizure discharges in hippocampal tissue slices.…”

Ion Regulation in the Brain: Implications for Pathophysiology

“…It has been known for some time that exposing the brain to a high concentration of K + can induce epileptiform discharge (Feldberg and Sherwood 1957;Zuckermann and Glaser 1968;Korn and others 1987;Chamberlin and Dingledine 1989) and that excess K + is released from neurons during seizures. The exudation of excess K + and uptake of Na + during seizure discharges could be detected with ion-selective glass electrodes placed on the cortical surface (Meyer and others 1961) and the fluxes of Fig.…”

Effects on temperature of amines injected into the cerebral ventricles. A new concept of temperature regulation

“…Antipyretics are analgaesics, and the catecholamines, too, exert analgaesic effects when acting from the liquor spaces (Bass, 1914;Leimdorfer & Metzner, 1949;Feldberg & Sherwood, 1954, 1957 when applied directly to the hypothalamus (Myers, 1964) or when given subcutaneously (Radouco-Thomas, Nosal, Radouco-Thomas & Le Breton, 1959).…”