Study for autonomic response induced by emetic stimuli and their central neural mechanisms in rats

观察阿朴吗啡对大鼠自主神经反应的影响。静脉注射阿朴吗啡(0.1 mg/kg体重)后，可观察到明显的胃运动反应。阿朴吗啡引起的远端胃运动反应可分为两种类型。一种类型包括抑制相性收缩，这是在给药阿朴吗啡之后出现的。另一种是小幅时相收缩的频率增加，伴随胃张力增加，出现的延迟相对较长。近端胃和远端胃均未见松弛。这些胃运动反应对阿朴吗啡量(0.002-0.1 mg/kg体重)呈剂量-反应效应。此外，在用多潘立酮(1或2 m…)治疗前，静脉注射阿朴吗啡3或10 mg/kg体重，可观察到颌下唾液分泌。更多的阿朴吗啡(g/kg体重)或最后区(AP)消融后，阿朴吗啡引起的胃运动反应和唾液分泌消失。总之，阿朴吗啡给药后，大鼠表现出明确的自主神经现象。位于AP的多巴胺2样受体介导阿朴吗啡诱导的大鼠自主神经现象。静脉注射NK-1拮抗剂可抑制胃内压升高，并呈剂量依赖关系。疑核(NA)附近微量注射NK-1拮抗剂不影响时相收缩的抑制反应，但可减弱胃内压升高。向同一区域微量注射神经毒性药物，溶解于庞塔明天蓝溶液中的鹅膏油酸，也可减轻胃内压的增加。综上所述，阿朴吗啡引起的胃内压升高延迟时间相对较长，可能是由NA附近的NK1受体介导的。较少

The effects of apomorphine administration on the autonomic responses were investigated in rats. Distinctive gastric motor responses were observed after the intravenous administration of apomorphine (0.1 mg/kg body wt). Gastric motor responses in the distal stomach induced by apomorphine administration were classified into two types. One type involved inhibition of phasic contractions which appeared just after the administration of apomorphine. The other involved an increase in the frequency of small phasic contractions accompanied by increased gastric tone appearing with a relatively longer delay. No relaxation was observed in either the proximal or distal stomach. These gastric motor responses showed a dose-response effect to the amount of apomorphine administered (0.002 - 0.1mg/kg body wt). In addition, submandibular salivary secretion was observed in response to the intravenous administration of apomorphine at a dose of 3 or 10 mg/kg body wt. Pre-treatment with domperidone (1 or 2 m … More g/kg body wt) or the ablation of the area postrema (AP) abolished the gastric motor response and salivary secretion induced by the administration of apomorphine. In conclusion, rats showed definitive autonomic phenomena in response to the administration of apomorphine. Dopamine 2-like receptors situated in the AP mediate apomorphine-induced autonomic phenomena in rats. Pretreatment of intravenous NK-1 antagonist diminished the increase in intragastric pressure, dose-dependently. Microinjection of NK-1 antagonist into the vicinity of the nucleus ambiguus (NA) did not influence on the inhibitory response of the phasic contractions but diminished the increase in intragastric pressure. Microinjection of neurotoxic agents, ibotenic acid dissolved in pontamine sky blue solution, into the same area also diminished the increase in intragastric pressure. In conclusion, increase in intragastric pressure, which appeared with relatively longer delay after the apomorphine administration, may be mediated by NK1 receptors in the vicinity of the NA. Less