Yoshimatsu H, Egawa M, Bray G A
Pennington Biomedical Research Center, Baton Rouge, LA 70808.
Brain Res. 1993 Jan 22;601(1-2):121-8. doi: 10.1016/0006-8993(93)91702-t.
In these experiments L-glutamate, an amino acid which stimulates neuronal discharge, was microinjected into several hypothalamic nuclei and the resultant changes in electrical firing rate of sympathetic nerves innervating interscapular brown adipose tissue (IBAT) were measured. Three patterns of response were seen. A single large stimulatory response was seen when L-glutamate was microinjected into the ventromedial hypothalamus (VMH). Microinjection of L-glutamate into the paraventricular nucleus (PVN) produced a predominantly stimulatory response which was of smaller magnitude than the VMN. However in three animals L-glutamate in the PVN decreased firing rate and in one animal a biphasic response was observed. The second pattern was a decrease in sympathetic activity to IBAT which was the predominant pattern following injection of L-glutamate into the dorsomedial hypothalamus (DMH). However, a biphasic pattern was also observed. Injection of L-glutamate into the lateral hypothalamic area (LHA) produced 3 patterns of response; an increase, a decrease; or a biphasic response in nearly equal numbers of animals. The predominant response to L-glutamate in the preoptic area (POA) was biphasic. These data are consistent with the hypothesis that the VMH is the predominant stimulatory site for activation of the sympathetic nervous system to IBAT in the rat. The DMH and LHA appear to be the predominant inhibitory areas.
在这些实验中，将能刺激神经元放电的氨基酸L-谷氨酸微量注射到几个下丘脑核中，并测量支配肩胛间棕色脂肪组织（IBAT）的交感神经放电率的相应变化。观察到三种反应模式。当将L-谷氨酸微量注射到腹内侧下丘脑（VMH）时，会出现单一的大刺激反应。将L-谷氨酸微量注射到室旁核（PVN）会产生主要为刺激的反应，但其幅度小于VMN。然而，在三只动物中，PVN中的L-谷氨酸降低了放电率，并且在一只动物中观察到双相反应。第二种模式是对IBAT的交感神经活动降低，这是将L-谷氨酸注射到背内侧下丘脑（DMH）后出现的主要模式。然而，也观察到双相模式。将L-谷氨酸注射到下丘脑外侧区（LHA）产生三种反应模式；在几乎相同数量的动物中，反应分别为增加、降低或双相。视前区（POA）对L-谷氨酸的主要反应是双相的。这些数据与以下假设一致，即VMH是大鼠中激活交感神经系统至IBAT的主要刺激部位。DMH和LHA似乎是主要的抑制区域。
