Changes of certain cardio-vascular parameters and the sympathetic nervous activity upon afferent vagal stimulation in...

Afferent stimulation of the cervical vagus in cats for 5 s upon bilateral vagotomy reduces systemic blood pressure by 15--50 percent. The maximum of this depressor reaction occurs 10--15 s after the beginning of the stimulation, its latency being 2--3 s. The decrease in the blood pressure is preceded by inhibition of the electrical activity of some preganglionic (n. splanchnicus) and postganglionic (n. cardiacus and n. renalis) sympathetic nerves with 100--200 ms latency. During the maximum pressure decrease activity appears in the above-mentioned nerves, afterwards the pressure begins to rise until its normalization. In addition to the decrease in systemic blood pressure changes are also observed in other cardio-vascular parameters, namely, decrease in the pressure in the left ventricle, decrease in the contractile force of the heart (dp/dt max) and of the heart rate.