The effects of long-term, low-dose diazepam treatment on the guinea pig righting reflex and medial vestibular nucleus neuronal activity

Guinea pigs received a 2 mg/kg IP injection of diazepam, or an equivalent volume of vehicle, daily for 28–60 days. To determine whether tolerance developed to the ataxic effects of diazepam on the righting reflex, daily righting reflex latency (RRL) measurements were made before and 20, 30, and 40 min following the diazepam or vehicle injection for 28 days. Analyses of the RRLs for individual animals indicated that a significant decrease in RRL over time (indicating tolerance) occurred in only one out of nine animals receiving diazepam and in none of the vehicle animals. Medial vestibular nucleus (MVN) neurons in brain stem slices from animals receiving chronic diazepam treatment had a significantly higher average firing rate than those from vehicle controls. These results suggest that: a) long-term treatment with single 2 mg/kg daily IP injections of diazepam does not result in tolerance to diazepam's ataxic effects on the righting reflex in the majority of animals; b) this form of diazepam treatment may, nonetheless, induce a hyperactivity of brain stem MVN neurons that may be consistent with the occurrence of a withdrawal syndrome.     

The isolated spinal cord-skin preparation of the newborn rat and effects of some algogenic and analgesic substances

We have developed an isolated spinal cord-skin preparation of the newborn rat. The spinal cord together with a piece of skin connected to the cord by the saphenous nerve was isolated from 1- to 4-day-old rats and separately superfused with artificial cerebrospinal fluid in two neighbouring chambers. Potentials were recorded extracellularly from the third lumbar ventral root. Application of capsaicin (0.5-2 μM) or KCl (60–350 mM) with brief pressure pulses to the perfusion bath of the skin evoked a depolarizing response of 20- to 40-s duration in the ventral root. The response was depressed by [Met⁵]enkcphalin (0.03–3 μM). morphine (0.1–2 μM) and a tachykinin antagonist, [D-Arg¹,D-Trp^7,9,Leu¹¹] substance P (spantide), 1–10 μM), applied to the spinal cord by superfusion, whereas the response was augmented by centrally administered calcitonin gene-related peptide (0.1–0.2 μM) or bicuculline (0.5–1 μM).     

Interactions between serotonin and substance P in the spinal regulation of nociception

Interactions between 5-hydroxytryptamine (5-HT) and substance P (SP) in the mouse spinal cord were investigated using the tail-flick test and the behavioral response evoked by intrathecal (i.th.) SP or i.th. 5-HT. I.th. injection of 5-HT (20 μg) or the 5-HT₁ receptor agonists(+)-8-hydroxy-2-(di-n-propylamino)tetralin ((+)-8-OH-DPAT) (20 μg) or 5-methoxy-3(1,2,3,6-tetrahydropyridine-4-yl)-1H-indole (RU 24969) (20 μg) markedly inhibited the tail-flick reflex. The effect of these compounds was reduced when SP (5 μg) was given i.th. 55 min, or 55 and 45 min before the agonists. The tail-flick latencies recorded 5 min before injection of a 5-HT agonist were similar in animals treated with SP or vehicle. The changes in the tail-flick test were not due to changes in tail skin temperature since only minimal differences in the skin temperature were recorded between the groups injected with SP or vehicle. I.th. injection of SP (10 ng) or 5-HT (2 μg) produced a similar behavioral response consisting of biting, licking and scratching of the caudal part of the body, indicative of nociceptive stimulation. The responses both to i.th. SP and 5-HT were reduced after i.th. application of SP receptor antagonist [d-Arg¹,d-Trp^7,9,Leu¹¹]-SP (Spantide) (5 μg), as well as 5 min after i.th. injection of the 5-HT receptor antagonist metergoline (4 μg). The data may indicate functional interactions between SP and 5-HT in the mouse spinal cord, which may take place in neurons involved in the processing of nociception.     

一氧化氮在氯胺酮麻醉机制中的作用

目的：了解一氧化氮（ＮＯ）与氯胺酮麻醉作用间的关系。方法：６０只雄性昆明鼠分成４组，Ⅰ组氯胺酮１００ｍｇ／ｋｇ腹腔内注射，Ⅱ组连续３天腹腔内注射Ｎ－硝基左旋精氨酸甲酯（Ｌ－ＮＡＭＥ）５０ｍｇ／ｋｇ后，腹腔内注射氯胺酮１００ｍｇ／ｋｇ，Ⅲ组连续３天腹腔内注射左旋精氨酸３００ｍｇ／ｋｇ后，腹腔内注射氯胺酮１００ｍｇ／ｋｇ，Ⅳ组腹腔内注射氯胺酮１００ｍｇ／ｋｇ后，腹腔１小时内持续给予Ｓ－亚硝酰－Ｎ－乙酰青霉胺（ＳＮＡＰ）３０ｍｇ／ｋｇ。观察各组动物翻正反射丧失和抑制持续时间。结果：各组翻正反射丧失时间无明显差异，为１．３９～２．３０分钟。翻正反射丧失持续时间Ⅰ组４７．７１±５．１７分，Ⅱ组４７．８４±７．９９分，Ⅲ组和Ⅳ组明显比Ⅰ、Ⅱ组短，分别为３１．１４±２．４４和３２．７５±８．１４分（Ｐ＜０．０１）。结论：改变ＮＯ的生成量将影响着氯胺酮引起的小鼠翻正反射抑制的持续时间，ＮＯ在氯胺酮麻醉分子机制中起作用。     

Quantitative relationship between pupillary reflex feature and its diopter in retinoscopy

ＱｕａｎｔｉｔａｔｉｖｅｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｐｕｐｉｌｌａｒｙｒｅｆｌｅｘｆｅａｔｕｒｅａｎｄｉｔｓｄｉｏｐｔｅｒｉｎｒｅｔｉｎｏｓｃｏｐｙＸｕＳｈａｎｇ（徐上）；ＪｉＳｈａｎｇｎｉａｎ（计尚年）（ＤｅｐａｒｔｍｅｎｔｏｆＯｐｈｔｈ...     

Orbicularis oculi responses to stimulation of nerve afferents from upper and lower limbs in normal humans

A brief mechanical or electrical stimulus to peripheral nerve afferents from the upper and lower limbs elicited a small and inconsistent EMG response of the orbicularis oculi muscles. This response was facilitated when the stimuli were delivered at fixed leading time intervals, of 45–300 ms, with respect to a supraorbital nerve electrical stimulus. Also, the peripheral nerve stimulus modified the conventional blink reflex responses, inducing facilitation of R1 and inhibition of R2. These results suggest a complex processing of sensory inputs from the face and the limbs at the brainstem, where they are probably integrated in a network of interneurons influencing the excitability of facial motoneurons.     

Analgesic actions of dynorphin A(1–13) antiserum in the rat brain stem

This study was performed to evaluate the effects of dynorphin A(1–13) antiserum when microinjected into an active hyperalgesic region within the rat brain stem. When administered within the dorsal posterior mesencephalic tegmentum (DPMT) of intact conscious rats, dynorphin A(1–13) antiserum produced rapid onset and persistent prolongation of a low intensity thermally evoked tail avoidance response (LITETAR). These analgesic actions of the dynorphin A(1–13) antiserum appeared to be dose dependent. These studies support previous hypotheses about the existence of tonically active brain stem opioid hyperalgesic processes. Further, the results provide indirect evidence for a potential role of brain stem dynorphin(s) in facilitating pain.     

Clinical and manometric evaluation of anorectal function following low anterior resection with low anastomotic line using an EEA™ stapler for rectal cancer

Anorectal function was evaluated in eight patients who had low anterior resection of the rectum with a low anastomotic line, using an EEA^™ stapler, with determination of function based on periodic manometric studies and clinical symptoms. Immediately following surgery all patients suffered from frequent bowel actions and soiling. These symptoms improved with time and most patients could enjoy almost normal daily life by the sixth postoperative month. One month after surgery, anal canal resting pressure and maximum squeeze pressure were significantly reduced and rectoanal inhibitory reflex was absent; neither showed a distinct tendency to improve thereafter. Rectal sensation and reservoir capacity, which also were seriously impaired, recovered satisfactorily by the time of the six-month examination. This suggests that an improvement of clinical symptoms following this operation is dependent upon the recovery of reservoir capacity and sensation of the neorectum, and that this operative procedure is a functionally acceptable option for low rectal cancer.     

单一电铃电路条件性行为疗法在建立儿童自主排尿反射中的作用研究

本工作在于探讨单一电铃电路条件性训练在建立儿童自主排尿反射中的治疗作用。采用新型研制的电铃电路床单，将电铃声刺激与膀胱充盈刺激有效的吻合起来，夜间训练遗尿患儿清醒后自主排尿。对年龄５～１０岁，经多项检查诊断确定为功能性遗尿的患儿（男１８名，女４名）２２人施行条件性行为训练方法。临睡的铺平电铃电路床单、患儿遗尿初期浸湿床单，引起铃响（患儿不惊醒时由母亲唤醒），患儿起床自主排尿。采用阳性强化法对患儿自主排尿进行巩固，给予原发以及继发性奖赏。结果：单一电铃电路条件性训练平均１２个有效治疗日后，９４．９７％（１８／１９）患儿遗尿症状消失，其中效果最佳者仅用了３个有效治疗日，最后长的达３０个有效治疗日，２人因故中断治疗，１人治疗无效。可见，单一行为方法是一条治疗儿童功能性遗尿的有效措施。