Vagus stimulation effects during various doses of fluid infusion in dogs

Stimulation of caudal and cranial ends of vagi in vagotomised chloralose-urethane anaesthetised dogs with 7.5V, 30Cps pulses of 2 msec width after 0, 25, 50, 75 and 100 ml/kg body weight infusion dose of Ringer-Locke solution caused well known effects on heart rate, BP, amplitude of peripheral blood pressure waves, amplitude and frequency of respiration and amplitude of ECG waves. The vagal stimulation effects did not appear to be related to volume of fluid infused into circulation except that caudal end stimulation effect on QRS amplitude was prominent during higher infusion doses while its effect on amplitude of peripheral blood pressure waves and respiration was prominent during lower infusion doses.