CARDIOVASCULAR RESPONSES OF DIVING AND NONDIVING MAMMALS TO APNEA.
Technical rept., Jan-Jul 65,
RUTGERS - THE STATE UNIV NEW BRUNSWICK N J DEPT OF PHYSIOLOGY AND BIOCHEMISTRY
Pagination or Media Count:
Heart rate, arterial and right atrial blood pressure, and cardiac output were monitored continuously before and during periods of apnea in anesthetized nutria and cats. In the nutria, arterial blood pressure was maintained an average of 182 seconds after profound bradycardia developed despite a decreased cardiac output. In cats arterial blood pressure began to decrease at 81 plus or minus 5.5 seconds, an average of 51 seconds before profound bradycardia was observed. The increase in peripheral resistance during apnea in cats was less than 20 of that found in nutria. Evidence of cardiac failure was found before bradycardia in the cat, but not in the nutria. It was concluded cardiovascular responses reported for diving mammals could be initiated by hypoxia and hypercapnia independent of intrathoracic pressure changes and the response of receptors in the nares sensitive to water. Author
- Anatomy and Physiology