Nasopharyngeal stimulation with cigarette smoke in rabbits demonstrated that the respiratory reflex is predominantly integrated at bulbospinal sites, whereas the cardiovascular reflex involves suprabulbar sites.
How do different central nervous regions control the reflex apnea, bradycardia, and mesenteric vasoconstriction evoked by nasopharyngeal stimulation in rabbits?
This preclinical study demonstrates that respiratory reflexes to nasopharyngeal stimulation are integrated at bulbospinal sites, while cardiovascular reflexes involve both bulbospinal and suprabulbar regions.
The role of different central nervous regions in the reflex apnea, bradycardia, and mesenteric vasoconstriction evoked by nasopharyngeal stimulation with cigarette smoke was examined in unanesthetized shamoperated, thalamic, and pontine rabbits with intact and sectioned carotid sinus and aortic nerves (CS and AN). Apnea occurred in all preparations. In pontine animals with intact CS and AN, the heart rate response was reduced but not the mesenteric vasoconstriction. The role of suprabulbar and bulbospinal regions became more apparent when individual components of the input profile were examined in animals with controlled ventilation. The bradycardia and mesenteric vasoconstriction evoked by apnea without smoke, but not by smoke without apnea, were reduced in pontine animals. Prior section of the CS and AN attenuated the response in all neural preparations but to the least extent when cerebral hemispheres were intact. The data indicate that the respiratory reflex is predominantly integrated at bulbospinal sites, but the cardiovascular reflex is integrated at both bulbospinal and suprabulbar sites, or is integrated at bulbospinal and modulated from suprabulbar sites.
White et al. (1975) studied this question. Nasopharyngeal stimulation with cigarette smoke vs. Different neural preparations (sham-operated, thalamic, pontine) was evaluated on Reflex apnea, bradycardia, and mesenteric vasoconstriction. Nasopharyngeal stimulation with cigarette smoke in rabbits demonstrated that the respiratory reflex is predominantly integrated at bulbospinal sites, whereas the cardiovascular reflex involves suprabulbar sites.