Fitzgerald R S, Shirahata M, Ide T
Department of Environmental Health Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205, USA.
J Appl Physiol (1985). 1997 Mar;82(3):819-27. doi: 10.1152/jappl.1997.82.3.819.
From the 1930s into the 1970s, the role of acetylcholine (ACh) in the carotid body's chemotransduction of hypoxia was debated. Since the late 1970s, the issue has been pursued only intermittently or not at all. The purpose of this study was to test again with a new preparation the hypothesis that ACh is an excitatory neurotransmitter in the cat carotid body's chemotransduction of hypoxia. We tested the effect of the specific nicotinic blocker mecamylamine and the muscarinic blocker of all five muscarinic receptors, atropine. We further tested the effects of M1 and M2 muscarinic-receptor blockers. The carotid body region was selectively perfused with hypoxic Krebs-Ringer bicarbonate (KRB) solutions that were blocker free or contained varying doses of the blockers. Both mecamylamine and atropine reduced the response to hypoxic KRB in a dose-related manner. The M2 muscarinic-receptor blockers gallamine and AFDX 116 increased the response to hypoxic KRB, whereas the M1 muscarinic-receptor blocker pirenzepine reduced the response to hypoxic KRB. These data are consistent with an excitatory role for ACh in the carotid body chemotransduction of hypoxia in the cat.
从20世纪30年代到70年代，乙酰胆碱（ACh）在颈动脉体对低氧的化学转导中的作用一直存在争议。自20世纪70年代末以来，这个问题只是间歇性地被研究，或者根本没有被研究。本研究的目的是用一种新的制剂再次检验ACh在猫颈动脉体对低氧的化学转导中是一种兴奋性神经递质的假说。我们测试了特异性烟碱受体阻滞剂美加明和所有五种毒蕈碱受体的毒蕈碱受体阻滞剂阿托品的作用。我们进一步测试了M1和M2毒蕈碱受体阻滞剂的作用。用不含阻滞剂或含有不同剂量阻滞剂的低氧 Krebs-Ringer 碳酸氢盐（KRB）溶液选择性灌注颈动脉体区域。美加明和阿托品均以剂量相关的方式降低了对低氧KRB的反应。M2毒蕈碱受体阻滞剂加拉明和AFDX 116增加了对低氧KRB的反应，而M1毒蕈碱受体阻滞剂哌仑西平降低了对低氧KRB的反应。这些数据与ACh在猫颈动脉体对低氧的化学转导中起兴奋作用一致。
