摘要
Experiments were performed on SD rats. The animals were anesthetized with urethane (1. 0 g/kg, i. p. ). The diaphragmatic electric activity and intratracheal pressure were monitored. Morphine (4 mg/kg, i. v. ) caused marked respiratory inhibition. The respiratory frequency (RF), integrated diaphragmatic electric activity (IDEA) and diaphragmatic minute activity (DMA) were decreased. The respiratory depression effect of morphine was almost completely eliminated by pretreatment with naloxone injected into the medial areas of the nucleus retrofacialis (mNRF). Bilateral microinjection of morphine (5 μg) into mNRF might result in apnea in all animals. This effect could be fully prevented by injection of naloxone into mNRF in advance. The results suggest that there might be morphine receptors in the mNRF and they might play an important role in the respiratory inhibition induced by systemic administration of morphine.
Experiments were performed on SD rats. The animals were anesthetized with urethane (1. 0 g/kg, i. p. ). The diaphragmatic electric activity and intratracheal pressure were monitored. Morphine (4 mg/kg, i. v. ) caused marked respiratory inhibition. The respiratory frequency (RF), integrated diaphragmatic electric activity (IDEA) and diaphragmatic minute activity (DMA) were decreased. The respiratory depression effect of morphine was almost completely eliminated by pretreatment with naloxone injected into the medial areas of the nucleus retrofacialis (mNRF). Bilateral microinjection of morphine (5 μg) into mNRF might result in apnea in all animals. This effect could be fully prevented by injection of naloxone into mNRF in advance. The results suggest that there might be morphine receptors in the mNRF and they might play an important role in the respiratory inhibition induced by systemic administration of morphine.
