Abstract: | The experiments carried out showed the presence- in sympathetic nerve endings ot the carotid sinus- of alpha and beta adrenoceptors which by means of respective negative and positive feedback processes, modulated NA release induced by a sympathetic nerve stimulation. Similarly, Pgs acted by means of a negative feedback mechanism to regulated adrenergic neuro-transmission in carotid sinus but they could not be considered as the chemical mediators of either alpha or beta adrenoceptors. |