BLAKEMORE Collin University Laboratory of Physiology, University of Oxford, 所長
NYE Piers G. University Laboratory of Physiology, University of Oxford, 講師
ROBBINS Peter A. University Laboratory of Physiology, University of Oxford, 講師
SAITO Toshihiro Department of Medicine, School of Medicine, Chiba University, 医学部, 講師 (40009593)
MASUDA Atsuko Department of Physiology, School of Medicine, Chiba University, 医学部, 助手 (70165710)
SAKAKIBARA Yoshikazu Kanazawa Institute of Technology, 教授 (50092060)
Using a new apparatus to induce a stimulation for the carotid baroreceptors (Neck suction method), effect of alterations of blood gas levels on baroreceptor activities was investigated.
Four different blood gas conditions were used i. e., 1) hypoxia (alveolar Po2, 50 mmHg), 2) hyperoxia (alveolar Po2, 200 mmHg), 3) hypercapnia (alveolar Pco2, 5mmHg higher than the control) and 4) combination of 1) and 3).
For neck suction, three degrees of negative pressure were applied, i. e., 20, 40 and 60mm Hg. Thus, combination of above conditions made us 12 different experimental procedures.
Main findings obtained were as follows :
1. Effect of baroreceptor stimulation was dominantly seen during expiratory phase.
2. Carbon dioxide stimulation was found to be inhibitory in all experimental conditions.
3. Positive interaction was seen in the effect between hypoxia and hypercapnia.
4. Effect of neck suction attained to be saturated between 40 to 60 mmHg.
Sine the effect of hypoxia was not so marked as expected, brain blood flow was measured by using a laser Doppler method to elucidate the possible explanation. The time course to increase brain blood flow in response to hypoxia and hypercapnia was compared.
Since the grant to proceed this joint study was afforded at the very end of the fiscal year, the detailed analysis of the data is still in process.