CALCITONIN RECEPTORS IN THE RAT MESENCEPHALON MEDIATE ITS ANALGESIC ACTIONS - AUTORADIOGRAPHIC AND BEHAVIORAL-ANALYSES
CALCITONIN RECEPTORS IN THE RAT MESENCEPHALON MEDIATE ITS ANALGESIC ACTIONS - AUTORADIOGRAPHIC AND BEHAVIORAL-ANALYSES
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DOI：
10.1016/0006-8993(85)90736-x
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发表时间：
1985-01-01
期刊：
影响因子：
2.9
通讯作者：
PERT, A
中科院分区：
文献类型：
--
作者：
FABBRI, A;FRAIOLI, F;PERT, A
放射自显影分析鲑鱼降钙素（sCT）结合在大鼠中脑显示异常高浓度的受体在腹侧和腹外侧段的导水管周围灰质（PAG）延伸沿着整个喙尾轴。沿沿着一条穿过中脑网状结构腹外侧延伸的带也可见相对较重的标记。其他受体丰富的区域包括黑质的线状核、睫状体部和外侧核、蓝斑、臂旁核和脑桥网状结构的中缝核点。将sCT注射到PAG中诱导热板潜伏期呈剂量依赖性增加。这些脑区的所有头尾部水平似乎都同样敏感。中线脑桥网状结构的注射也有效地增加了反应延迟。下丘脑、内侧丘脑、腹侧丘脑和中脑网状结构的单侧注射被证明是无效的。人降钙素（hCT）的效力要低得多。这些生物学效应与两种肽从大鼠PAG载玻片切片中置换125 I-sCT的效力一致。纳洛酮未能拮抗sCT诱导的镇痛，表明这种肽在引起镇痛中的阿片非依赖性机制。
Autoradiographic analyses of salmon calcitonin (sCT) binding in the rat mesencephalon revealed an exceptionally high concentration of receptors in the ventral and ventrolateral segments of the periaqueductal gray matter (PAG) extending along the entire rostral-caudal axis. Relatively heavy labeling was also seen along a band extending ventrolaterally through the mesencephalic reticular formation. Other receptor-rich areas include the nucleus linearis, pars compacta and lateralis of the substantia nigra, locus coeruleus, parabranchial nuclei and nucleus raphe points of the pontine reticular formation. Injections of sCT into the PAG induced a dose-dependent increase in hot-plate latencies. All rostral-caudal levels of these brain regions appeared to be equally responsive. Injections into the midline pontine reticular formation were also effective in increasing response latencies. Unilateral injections into the hypothalamus, medial thalamus, ventral thalamus and mesencephalic reticular formation proved to be ineffective. Human calcitonin (hCT) was considerably less potent. These biological effects are consistent with the potencies of both peptides in displacing 125I-sCT from slide-mounted sections of rat PAG. Naloxone failed to antagonize sCT-induced analgesia, suggesting an opiate independent mechanism for this peptide in eliciting analgesia.