Left and right superior cervical ganglionectomy affect differently the cardiorespiratory patterning in the in situ arterially perfused brainstem preparation of the rat

Abstract

The superior cervical ganglia project to the nucleus tractus solitarii, modulate vasomotor tone and buffer cardio‐respiratory responses to chemoreceptor activation. Here, we report the differential effect of left versus right superior cervical ganglionectomy (SCGx) on cardiorespiratory activity in the in situ arterially perfused brainstem preparation. For these studies, we used male Sprague‐Dawley rat pups (P25). Four days after removal of either the left or right superior cervical ganglia (n=20, 10 in each side) or sham surgery (n=10), we recorded left and right phrenic (PNA) and cervical vagal (VNA) nerve activities, and monitored perfusion pressure. ‘Fictive’ cardio‐respiratory patterns were recorded for 10 min (baseline) and then in response to peripheral chemoreceptor activation (intra‐arterial injection of sodium cyanide, 100 μL of a 0.03% solution). At baseline and during the response to chemoreceptor stimulation, the left and right PNA and VNA were similar for all groups. At baseline, PNA burst frequency and amplitude were similar in the left‐, right‐ SCGx and sham groups but VNA was greatest for the left SGX group and the perfusion pressure had to be increased to maintain ‘fictive’ respiration for right‐SCGx group. During the chemoreceptor stimulation, the fR response was greatest for the sham group and greater for the right‐ than the left‐SCGx group. In contrast, the PNA amplitude response was greatest for right‐SCGx group and comparable for the left‐SCGx and sham groups. Despite the increase in baseline VNA, the increase in VNA response to chemo‐stimulation was similar for the left‐, right‐SCGx and sham groups. Finally, the left‐SCGx group had smallest increase in PP during chemoreceptor stimulation. These data indicate that the left and right superior cervical ganglia modulate vasomotor tone respiratory patterning differentially at rest and during chemoreceptor reflexes.Support or Funding InformationNIH SPARC 1OT2OD023860‐02 SJ LewisThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.