Experimental cerebrovscular disorders: Effects on cardiovascular functions and on cerebrospinal fluid production and constituents with special reference to cyclic AMP

Abstract

A possible significance of measuring cerebrospinal fluid cyclic adenosine 3′,5′-monophosphate (cAMP) concentration to quantitate a central nervous system ischemic lesion was studied in cats and rabbits. Carotid occlusion and subsequent intracarotid liquid paraffin injection were used for producing an experimental model for cerebrovascular disorders. The manipulations adopted were found to alter markedly arterial blood pressure and heart rate of anesthetized animals, but not to cause any statistically significant changes in cerebrospinal fluid production or in its cAMP concentration. Long term study of experimental cerebrovascular disorders in rabbits revealed that ether anesthesia itself, 15 to 20 min in duration, transiently increased the cAMP concentration within the first hour [from 32.2 ± 1.8 n m (SE) to 43.4 ± 4.3 n m, P < 0.005). Thereafter, compared to their respective basal values, cAMP concentrations in cerebrospinal fluid were elevated in animals which had undergone carotid occlusion combined with intracarotid liquid paraffin injection, at the third postoperative hour ( P < 0.02) as well as in rabbits 3 ( P < 0.05) and 24 h ( P < 0.001) after carotid occlusion alone. The alterations of protein concentartion synchronized rather well with those of the cAMP concentration. On the basis of these experimental findings, measuring cerebrospinal fluid cAMP concentration in clinical practice and the quantitation of some attendant neurological changes may be anticipated to be of help.