Keay K A, Redgrave P, Dean P
Department of Psychology, University of Sheffield, England.
Brain Res Bull. 1988 Jan;20(1):13-26. doi: 10.1016/0361-9230(88)90004-4.
Stimulation of the rat superior colliculus can produce either orienting or defensive movements, which if elicited by natural stimuli would be accompanied by cardiovascular changes. To assess whether cardiovascular changes might also be mediated by the superior colliculus, blood pressure and heart rate were measured in Saffan-anaesthetised rats while the dorsal midbrain was systematically explored with electrical and chemical stimulation. Electrical stimulation (10 sec trains of 0.3 msec 100 Hz cathodal pulses, 50 microA) within the superficial and intermediate layers of the rostral superior colliculus transiently lowered blood pressure without affecting heart rate. In contrast sites within the deep layers, and in adjacent periaqueductal grey and midbrain tegmentum, gave pressor responses accompanied by a variety of heart-rate changes, that usually included a period of bradycardia. A roughly similar distribution was obtained with the cell-stimulant bicuculline (200 or 500 nl, 490 microM), though sodium L-glutamate (200 nl, 0.05 or 1.0 M) was ineffective. These results suggest that (a) cardiovascular responses can be produced by stimulation of the rat superior colliculus; (b) their nature depends on the location of the stimulation; and (c) they may be mediated in part by cells differentially sensitive to glutamate and to bicuculline. In addition, in some animals respiratory responses were measured stethographically. Short-latency increases in thoracic girth, often accompanied by increases in respiratory rate and depth, were elicited by electrical stimulation from 61% of the collicular sites examined, and by microinjection of glutamate from 56% of collicular sites. These data suggest that (a) cells within the superior colliculus are capable of influencing respiration; (b) given the widespread distribution of responsive sites within the superior colliculus, the respiratory changes may be preparatory for both approach and defensive movements; (c) the collicular cells that affect respiration may be different from those that influence blood pressure, because the latter are relatively insensitive to microinjection of glutamate.
刺激大鼠上丘可产生定向运动或防御性运动，若由自然刺激引发，这些运动将伴有心血管变化。为评估心血管变化是否也可由上丘介导，在戊巴比妥钠麻醉的大鼠中测量血压和心率，同时用电刺激和化学刺激系统地探索背侧中脑。在 Rostral 上丘浅层和中间层内进行电刺激（10 秒时长的 0.3 毫秒 100 赫兹阴极脉冲，50 微安）可使血压短暂降低，而不影响心率。相比之下，深层以及相邻的导水管周围灰质和中脑被盖区域的刺激部位则产生升压反应，并伴有多种心率变化，通常包括一段心动过缓期。用细胞兴奋剂荷包牡丹碱（200 或 500 纳升，490 微摩尔）可得到大致相似的分布，不过 L - 谷氨酸钠（200 纳升，0.05 或 1.0 摩尔）无效。这些结果表明：（a）刺激大鼠上丘可产生心血管反应；（b）其性质取决于刺激的位置；（c）它们可能部分由对谷氨酸和荷包牡丹碱敏感性不同的细胞介导。此外，在一些动物中用听诊法测量呼吸反应。电刺激 61%的所检查的上丘部位以及从 56%的上丘部位微量注射谷氨酸可引发胸围短潜伏期增加，常伴有呼吸频率和深度增加。这些数据表明：（a）上丘内的细胞能够影响呼吸；（b）鉴于上丘内反应部位分布广泛，呼吸变化可能是接近和防御性运动的准备；（c）影响呼吸的上丘细胞可能与影响血压的细胞不同，因为后者对微量注射谷氨酸相对不敏感。
