Mauad H, Colombari E, Bonagamba L G, Machado B H
Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
Braz J Med Biol Res. 1995 Jun;28(6):699-704.
Microinjection of L-glutamate into the nucleus tractus solitarii (NTS) of conscious freely moving Wistar rats (240-260 g) produces pressor (+48 +/- 4 mmHg) and bradycardic (-153 +/- 20 bpm) responses. In the present study L-glutamate (2.5 nmol/100 nl) was microinjected before and after microinjection of increasing doses of glycine (10, 25 and 50 nmol/100 nl, N = 6) or saline (vehicle/100 nl, N = 6) into the NTS. Microinjections of increasing doses of glycine into the NTS produced a dose-dependent reduction in the pressor but not in the bradycardic responses to L-glutamate. [10 nmol (+29 +/- 5 mmHg and -110 +/- 18 bpm), 25 nmol (+12 +/- 7 mmHg and -88 +/- 21 bpm) and 50 nmol (+4 +/- 2 mmHg and -100 +/- 31 bpm)] The dose-dependent blockade of the pressor response to L-glutamate by glycine suggests an inhibitory neuromodulatory role for this amino acid in the sympatho-excitatory activity produced by L-glutamate microinjection into the NTS.
向清醒自由活动的Wistar大鼠（240 - 260克）的孤束核（NTS）微量注射L - 谷氨酸会产生升压反应（+48±4 mmHg）和心动过缓反应（-153±20次/分钟）。在本研究中，在向NTS微量注射递增剂量的甘氨酸（10、25和50纳摩尔/100微升，N = 6）或生理盐水（溶剂/100微升，N = 6）之前和之后，均微量注射L - 谷氨酸（2.5纳摩尔/100微升）。向NTS微量注射递增剂量的甘氨酸会使对L - 谷氨酸的升压反应呈剂量依赖性降低，但对心动过缓反应无此影响。[10纳摩尔（+29±5 mmHg和-110±18次/分钟），25纳摩尔（+12±7 mmHg和-88±21次/分钟）和50纳摩尔（+4±2 mmHg和-100±31次/分钟）]甘氨酸对L - 谷氨酸升压反应的剂量依赖性阻断表明，该氨基酸在向NTS微量注射L - 谷氨酸所产生的交感兴奋活动中具有抑制性神经调节作用。
