The effect of the adrenocorticotropic hormone on the state of the skin receptors

Abstract

A study was made of the effect produced by ACTH on the state of cutaneous receptors of rabbit and frog. The hormone was administered to rabbits twice (in a dose of 5 units/kg) and to frogs once (5 units/animal). Receptors were stimulated by an automatic “toucher”, and in frog — by Frey's hairs and sulfuric acid solutions. Impulses appeaning in the skin nerve were recorded with the aid of a loop, oscillograph. Prior to this, determination of the reflex time was done in frogs after Turck. Excitability of rabbits diminished and reflex time of frogs increased after the ACTH administration. The impulse discharge considerably decreased after stimulation with an automatic “toucher”. With constant pressure by Frey's hairs receptor adaptation occurred very rapidly. The excitation threshold of tactile receptors and of receptors reacting to acid showed an essential rise, whereas the reaction of receptors to weak stimuli declined. Along with a reduction of receptor excitation there was a rise of receptor resistance to strong stimuli. In the latter instance the impulsation greatly decreased in control experiments, which did not occur after the ACTH administration.