[Relationship between central beta-endorphins and serotonin systems in mechanism of hypoxic ventilatory regulation].
Experiments were performed on anesthetized bilaterally chemodenervated rabbits. After giving hypoxic gas mixture (10% O2 in N2) to animals to cause ventilatory inhibition, lateral ventricle applications of beta-endorphins (beta-EP) antagonist naloxone (Nlx) and agonist ohmefentanyl (OMF) respectively reduced and enhanced hypoxia-induced ventilatory inhibition. Meanwhile the level of central serotonin (5-HT) was obviously increased more than that before the drug administration. Injection of exogenous 5-HT into rabbit lateral ventricle induced central beta-EP content to decrease markedly while minute ventilation (VE) was returned to control at the same time. The results suggest that beta-EP system in CNS is the basic and direct element in the regulatory mechanism of hypoxic ventilatory inhibition, and central 5-HT system only acts as a neuromodulator in modulating the activity of beta-EP system to indirectly affect ventilatory response to hypoxia.
Xu
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Shanghai Institute of Physiology, Academia Sinica.
Hu
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ST
D000818:Animals; D005283:Fentanyl / Q000031:analogs & derivatives / Q000494:pharmacology; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D007276:Injections, Intraventricular; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D011817:Rabbits; D012119:Respiration; D012701:Serotonin / Q000378:metabolism*; D001615:beta-Endorphin / Q000378:metabolism*
D012701:Serotonin; D009270:Naloxone; D001615:beta-Endorphin; C037016:F 7302; D005283:Fentanyl