The contribution of the sympathetic nervous system to the development and maintenance of experimental hypertension in the rat.

1. Experimental hypertension in the rat, induced either by renal artery stenosis or by treatment with deoxycorticosterone acetate (DCA) developed maximally over a period of 8 weeks. In both types of hypertension the rate of development was unaffected by immunosympathectomy or by chemical sympathectomy following the administration of 6-hydroxydopamine.

The effect of some foreign anions on suxamethonium blockade of the isolated rat diaphragm preparation.

1. The pharmacology of suxamethonium blockade of the rat phrenic nerve-diaphragm preparation has been studied in the presence of some foreign anions.2.

The role of the sympathetic nervous system in the cardiovascular responses to angiotensin in the pithed rat.

1. Angiotensin (200-500 ng, intravenously) produced a biphasic pressor response accompanied by reflex bradycardia in rats anaesthetized with sodium pentobarbitone. In pithed rats and in anaesthetized animals treated with a ganglion blocking agent there was a similar pressor response but an increase in the heart rate which was coincident with the second phase of the pressor response.

QUANTITATIVE EVALUATION OF GUINEA-PIG ANAPHYLAXIS IN VIVO.

Two methods for recording bronchoconstrictor responses to antigen injected into sensitized guinea-pigs have been used to show that the dose/response relationship is a normal pharmacological one characterized by a sigmoid curve. Studies of desensitization indicate that the progressive decrease in sensitivity to repeated administrations of the same dose of antigen follows an exponential pattern. It is suggested that this approach might form a basis for reliable quantitative investigations of anaphylactic phenomena.