Somatosensory evoked potentials during hypoxia and hypocapnia in conscious humans.

Purpose: The objective of the study was to evaluate the effects of moderate hypoxia and hypocapnia on the latency and amplitude of cortical somatosensory evoked potentials (SSEPs) in conscious human subjects.

Methods: In ten volunteers the amplitude and latency of the cortical somatosensory evoked potentials were recorded during stimulation of the left posterior tibial nerve. Measurements of SSEPs and respiratory variables were made breathing ambient air, air containing a reduced oxygen percentage (17% O2, 14% O2 (n = 6) or 11% O2 (n = 10)), and again during voluntary hyperventilation breathing ambient air (PETCO2 = 20 mmHg, n = 10).

Regulation of plasma vasopressin by plasma osmolality and carotid sinus pressure in anesthetized rabbits.

The purpose of the experiments was to investigate the effect of changes in carotid sinus baroreceptor stimulation on plasma vasopressin (AVP) at different plasma osmolalities in the anesthetized artificially ventilated rabbit. Both carotid sinuses were isolated and perfused with blood at servo-controlled pressures. The vagus and aortic depressor nerves were sectioned bilaterally to eliminate input from atrial and aortic arch baroreceptors.