P物质、亮氨酸脑啡肽、5-羟色胺样成分在新生儿中脑导水管周围灰质的分布

本文用PAP和ABC法对3例生后1—2天新生儿中脑导水管周围灰质(PAG)内P物质、亮氨酸脑啡肽、5-羟色胺样成分的分布进行了观察。发现P物质样阳性胞体主要位于PAG的中、尾段,分为位于腹外侧区的腹侧群和位于腹外侧区与背外侧区交界处的外侧群等两群。其阳性纤维和终末以背侧区为最密。亮氨酸脑啡肽样阳性胞体也出现于PAG中、尾段的各个区内,以腹外侧区数量为多,其阳性纤维及终末也以腹外侧区最密集。5-羟色胺样阳性胞体集中在PAG中、尾段的腹外侧区,其阳性纤维及终末主要分布于PAG的内侧区。本文还对此三种物质与镇痛机制的关系进行了讨论。     

Forebrain and lower brainstem participation in facilitatory and inhibitory regulation of the display of lordosis in female rats

Neural transection of the dorsal extrahypothalamic descending afferents by means of an L-shaped Halász knife at the anterior commissure (anterior roof deafferentation. ARD) markedly potentiated the display of lordosis and soliciting behaviors. Bilateral lesions of the ventromedial hypothalamus (VMH) attenuated lordotic activity in the ARD sham females but not in the ARD females. In contrast, the lesions in the pontine central gray concurrently with ARD effectively inhibited the display of lordosis but not soliciting behaviors. These results suggest that the VMH may not be a primary focus of the dorsal extrahypothalamic inhibitory influence on lordosis. The influence of this inhibitory system seems to be dominant in regulating the expression of lordosis behavior, compared to that of the hypothalamic lordosis facilitating system. Furthermore, the dorsal extrahypothalamic inhibitors influence which could be removed by ARD must be modified by the neural mechanism in the lower brain stem in which the pontine central gray may be actively involved.     

Laminar distribution and morphology of NADPH-diaphorase containing neurons in the superior colliculus and underlying periaqueductal gray of the rat

Summary We have studied the laminar distribution of reduced nicotinamide dinucleotide phosphate diaphorase (NADPH-d) activity and the morphology of positive neurons in the superior colliculus (SC) and the underlying periaqueductal gray (PAG) of the rat. The morphology of NADPH-d-positive neurons has been compared to that of Golgi-impregnated cells. The highest activity occurs in the stratum zonale and stratum griseum superficiale, contrasting with the pale neuropil in the stratum opticum, where only a few positive neurons are found. In the stratum griseum intermedium positive neurons are grouped in patches separated by narrow, NADPH-d-negative bands. In the deeper layers, the neuropil is NADPH-d-negative, and few neurons show enzymatic activity. In contrast, numerous neurons in the dorsolateral part of the PAG are intensely positive. They are continuous with the positive neurons in the stratum album profundum, with no clear border between the two centers. In both SC and PAG, only small and medium sized neurons are NADPH-d-positive. In comparison with Golgi material, all types of small neurons in the superficial layers show NADPH-d activity; NADPH-d histochemistry, however, does not visualize the characteristic dendritic appendages of these neurons. The large neurons of the SC and PAG, probably representing the long-projecting neurons of these centers, do not contain the enzyme.     

The role of descending inhibition in the antinociceptive effects of the pyrazolone derivatives,metamizol (dipyrone) and aminophenazone (“Pyramidon”)

Summary The study was carried out to provide further evidence that the two pyrazolone derivatives, metamizol and aminophenazone, produce central antinociceptive effects by stimulating inhibition descending from the periaqueductal grey (PAG) to the spinal cord. Experiments were carried out on rats in which the tail-flick response to radiant heat, nociceptive activity in ascending axons of the spinal cord, and activity of neurones in the PAG and the substantia nigra were studied. Microinjection of procaine (10 g) into the PAG reduced the tail-flick latency and abolished the increase in latency caused by i.p. injection of metamizol (40 mg/kg) and aminophenazone (150 mg/kg); it did not significantly reduce the antinociceptive effect of i.p. injection of morphine (2 mg/kg). Threshold doses of morphine (1 and 2 g) administered by intrathecal (i.t.) injection potentiated the effect of threshold doses of metamizol injected i.p. (10 mg/ kg) or into the PAG (10 g) in the tail-flick test. Morphine (2 g) injected i.t. potentiated the effect of i.v. injection of metamizol (80 mg/kg) on nociceptive activity in ascending axons by eliminating the stimulant effect of metamizol on about one third of the axons. Threshold doses of morphine injected i.t. failed to potentiate the antinociceptive effect of aminophenazone (50 mg/kg) injected i.p. in the tail-flick test. The results support the view that metamizol and aminophenazone activate pathways descending from the PAG and exerting an inhibitory effect on nociceptive impulse transmission at the spinal level.Supported by the Schwerpunkt Nociception and Schmerz of the Deutsche Forschungsgemeinschaft Send offprint requests to I. Jurna at the above address     

Changes in central serotoninergic transmission affect clonidine analgesia in monkeys

Summary 1. The effects of changes in central serotoninergic transmission on clonidine analgesia were assessed in monkeys. The minimum electrical current required for producing jaw opening is referred to as the pain threshold. Pain was induced by electrical stimulation of tooth pulp afferents. 2. In the first series of studies, intracerebroventricular administration of clonidine (5–30 g) produced dose-dependent analgesia in monkeys. The clonidine-induced analgesia was abolished or attenuated by prior injection of the animals with p-chlorophenylalanine or 5,7-dihydroxytryptamine into the third cerebral ventricle. On the other hand, pretreatment of the animals by injecting 5-HT or its precursor 5-hydroxytryptophan into the cerebral ventricle potentiated the clonidine-induced analgesia in monkeys. 3. In the second series of experiments, administration of clonidine (1–10 g) into the diencephalic periventricular gray (of the anterior hypothalamic portion), the periaqueductal gray, or the dorsal raphe nuclei also produced dose-dependent analgesia in monkeys. The analgesia induced by clonidine injection into the diencephalic periventricular gray or the periaqueductal gray was effectively antagonized by pretreatment of the animals by injecting two 5-HT receptor antagonists (such as ketanserine and methysergide) into the diencephalic periventricular gray or the periaqueductal gray. The clonidine-induced analgesia in monkeys was not affected by pretreatment of the animals with injections of either ketanserine or methysergide into the dorsal raphe nuclei. 4. The results suggest that the functional activity of central 5-HT neurons correlate well with the analgesic sensitivity of clonidine microinjected centrally. In addition, the analgesia induced by clonidine microinjected into the diencephalic periventricular gray or the periaqueductal gray was mediated by the 5-HT receptors at the site of injection.This study was supported by grants from the National Science Council of the Republic of China and the Student Summer Fellowship of National Cheng Kung University Medical College (1986) Send offprint requests to Mao-Tsun Lin at the above address     

团块状灰度变化减轻子宫良性疾病聚焦超声消融术中的远场不良反应

目的：评估团块状灰度变化能否减轻子宫良性疾病聚焦超声消融术中的远场不良反应。方法：开展单中心回顾性临床观察研究,纳入重庆医科大学附属第二医院行聚焦超声消融术的40例子宫良性疾病。比较团块状灰度变化出现前后,在相同能量水平（最小不可耐受能量）下,术中即刻骶尾部或臀部疼痛、放射痛、会阴部痛、肛门胀痛的发生率及不良反应程度。结果：在相同能量水平（最小不可耐受能量）下,团块状灰度变化出现后术中即刻骶尾部或臀部疼痛、放射痛、会阴部痛、肛门胀痛的发生率及不良反应程度明显低于团块状灰度变化出现前（P<0.05）。结论：团块状灰度变化能减轻子宫良性疾病聚焦超声消融术中的远场不良反应。     

中脑导水管周围灰质内注射抗强啡肽血清对神经降压素镇痛作用的影响

目的：探讨大鼠中脑导水管周围灰质（PAG）内内源性强啡肽对神经降压素（NT）镇痛作用的影响。方法：以钾离子透入法引起大鼠甩尾反应的电流强度（mA)为痛行为反应的指标,观察向PAG内注入NT,抗神经降压素血清和抗强啡肽A1－13血清对动物痛阈的影响。结果：PAG内注入NT后,大鼠痛阈明显升高;注入抗神经降压素血清后,大鼠痛阈则明显降低,而注入抗强啡肽血清后,对NT的镇痛效应无显著影响,结论：PAG内NT在痛觉调制中发挥着重要的作用,且其作用不依赖于PAG内的内源性强啡肽。