Involvement of the raphe in the respiratory effects of gigantocellular area activation.
Previous reports indicate that the nucleus reticularis gigantocellularis (NGC) of the brainstem reticular formation is involved in inhibitory respiratory and cardiovascular reflexes. Stimulation of portions of the nearby bulbar raphe complex, specifically the raphe magnus (RM), have also been shown to suppress phrenic activity and to decrease blood pressure and heart rate. Since synaptic connectivity between the NGC and the RM has been demonstrated, we hypothesized that the RM may be involved in the cardiopulmonary effects of NGC stimulation. This study found that electrolytic lesions in the raphe magnus attenuated the inhibitory respiratory effects but not the cardiovascular suppression due to NGC stimulation. Lesions in the raphe magnus also lowered resting blood pressure and resting breath frequency. We conclude that the RM may mediate part of the NGC-mediated respiratory effects.
Richard
C A
CA
Department of Physiology and Biophysics, School of Medicine, University of Louisville, KY 40292.
Stremel
R W
RW
D000818:Animals; D001794:Blood Pressure; D002415:Cats; D004558:Electric Stimulation; D006339:Heart Rate; D006439:Hemodynamics; D008839:Microelectrodes; D010791:Phrenic Nerve; D011903:Raphe Nuclei / Q000502:physiology*; D012119:Respiration / Q000502:physiology*; D012154:Reticular Formation / Q000502:physiology*; D013238:Stereotaxic Techniques