Chronic administration of a selective dopamine D-2 agonist: factors determining behavioral tolerance and sensitization

The locomotor stimulant effects of sustained administration of a potent and selective dopamine (DA) D-2 receptor agonist, [+]-4-propyl-9-hydroxynaphthoxazine (PHNO), in rats were assessed 24 h a day during 12 h light-dark cycles. PHNO was administered continuously with subcutaneous implants of Alzet osmotic minipumps (5 g/h), for 12 h a day with modified osmotic minipumps (5 g/h), or by daily injections (15 g, SC). Tolerance was observed to occur only with 24 h continuous infusions and only during the light period. The other treatment regimens produced sensitization of the locomotor response. Daytime tolerance to continuous infusions of PHNO was reversed following reversal of the light-dark cycle. A normally arousing stimulus also reversed (temporarily) daytime tolerance. The present results indicate that the temporal pattern of administration of DA agonists, the phase of the circadian cycle and environmental stimuli associated with arousal are important determinants of the behavioral consequences of long-term treatment.     

麻醉诱导前给予右美托咪定对脊柱侧弯矫形术患者的影响

探讨麻醉诱导前给予右美托咪定对脊柱侧弯矫形术患者唤醒时间、镇痛效应及血流动力学的影响。方法 选取2021年1月～2021年12月间于我院行脊柱侧弯矫形术的患者113例为研究对象,按照简单随机法分为观察组（n=57）和对照组（n=56）,观察组在麻醉诱导前给予0.8 μg/kg的右美托咪定10 min内静脉泵注体内,对照组在相同时间内泵入等量的生理盐水,而后两组患者均行全身麻醉,比较两组麻醉插管前（T0）、插管后10 min（T1）、唤醒前10 min（T2）、唤醒期间（T3）、唤醒后5 min（T4）、加深麻醉后10 min血流动力学指标［心率（HR）、平均动脉压（MAP）、血氧饱和度(SpO2)］变化,术后唤醒时间、唤醒质量、唤醒时躁动发生率,拔管即刻、术后2、6、24 h镇痛效果［视觉模拟评分法（VAS）］,麻醉前、术后2 h及6 h应激反应［血清皮质醇（Cor）、醛固酮（ALD）、血糖（Glu）］水平及药物安全性。结果 HR、MAP组间、时间点、组间×时间点比较,差异均有统计学意义（P＜0.05）,观察组T3、T4时间段HR、MAP比较差异有统计学意义（P＜0.05）,SpO2组间、时间点、组间×时间点比较差异均无统计学意义（P＞0.05）。观察组唤醒质量显著高于对照组（P＜0.05）,唤醒时躁动发生率显著低于对照组（P＜0.05）,两组唤醒时间比较差异无统计学意义（P＞0.05）。VAS评分组间、时间点、组间×时间点比较,差异均有统计学意义（P＜0.05）,组内各时间段比较差异均有统计学意义（P＜0.05）,观察组术后2、6 h VAS评分显著低于对照组（P＜0.05）。Cor、ALD、Glu组间、时间点、组间×时间点比较,差异均有统计学意义（P＜0.05）,组内各时间段内外周血Cor、ALD、Glu水平均依次递增（P＜0.05）,且观察组术后2、6 h外周血Cor、ALD、Glu水平均显著高于对照组（P＜0.05）。观察组与对照组不良反应率比较,差异无统计学意义（2=0.154,P=0.694）。结论 脊柱侧弯矫形术麻醉诱导前给予右美托咪定有利于提高术中唤醒质量,降低术中血流动力学波动,改善术后疼痛及应激反应,具有良好的应用价值     

Hurricane Hugo blows down the broccoli: Preschoolers' post-disaster play and adjustment

This article reports highlights from over 200 parents' observations of their preschoolers' play and verbalizations in the year following Hurricane Hugo. Commonly reported activities included reenactment and discussion of the event in multiple mediums, personification of Hugo, and expression of fears related to storms. Precocious concern for others, insight, and vocabulary were also noted. In these intact, relatively high functioning families, parents seemed able to facilitate their youngsters' adjustment without outside intervention.Portions of this report were presented in earlier form at the 1991 Society for Research in Child Development meeting in Seattle, Washington.     

Neuroendocrine responses to nicotine and stress: enhancement of peripheral stress responses by the administration of nicotine

Habitual smokers frequently report that when they are stressed smoking helps them to relax. One potential explanation for the reported stress ameliorating effect of smoking is that cigarette consumption (nicotine self-administration) may decrease the sympathetic autonomic nervous system activity which is associated with the stress response. In the present study, rabbits prepared with chronic vascular cannulae were used to study the effects of nicotine administation on plasma corticosterone, catecholamine (epinephrine, norepinephrine and dopamine) and glucose responses to physical restraint stress. Nicotine (0.025, 0.05 or 0.10 mg nicotine base/kg body weight) was administered for 10 days prior to the stress test to allow for the development of habituation/tolerance to its acute toxic effects. Independent administration of nicotine, or the application of the physical restraint stressor, resulted in increases in the plasma concentrations of corticosterone, epinephrine, norepinephrine, and glucose. Nicotine administration during restraint stress enhanced the increase in plasma corticosterone and epinephrine, as compared to the responses induced by either factor alone. The results suggest that the stress ameliorating effect of continued cigarette smoking, as reported by habitual smokers, is not due to a reduction in the activity of the peripheral sympathetic autonomic nervous system.     

Individual Differences in Plasma Catecholamine and Corticosterone Stress Responses of Wild-Type Rats: Relationship With Aggression

Plasma noradrenaline (NA), adrenaline (A), and corticosterone (CS) responses to social and nonsocial stressors were studied in male members of a strain of wild-type rats, widely differing in their level of aggression. The aggressiveness was preliminarily established by measuring the latency time to attack (ALT) a male intruder in a standard resident-intruder test. Animals were then provided with a jugular vein cannula for blood sampling during stress exposure. Implanted rats were randomly assigned to 3 experimental treatments: social stress (defeat experience, SD), nonsocial stress (presentation of a shock-prod, SP) and control (animals undisturbed in their home cages, CTR). A significant correlation was found between ALT and the amount of time spent in burying the probe in SP rats: the more aggressive the animal, the higher the rate of burying behavior. SD induced a much stronger effect on plasma NA, A, and CS concentrations than SP. A significant negative correlation was found between ALT scores and values of the area under the response time curve for NA and A, in both SD and SP situations: the more aggressive the animal, the higher the catecholaminergic reactivity to the stressors. On the contrary, no evidence of a correlation between aggressiveness and plasma corticosterone responses was found, neither in SD nor in SP rats. These findings in an unselected strain of wild-type rats confirmed that an aggressive/active coping strategy is associated with a high sympathetic-adrenomedullary activation and support the concept of individual differentiation in coping styles as a coherent set of behavioral and neuroendocrine characteristics.     

The effect of a high calory diet on hormonal changes in young men during prolonged physical strain and sleep deprivation

Summary Major changes occur in the serum level of several hormones during 5 days of heavy and continuous physical activities, with less than a total of 2 h of sleep. The present investigation was designed to evaluate the importance of caloric deficiency, energy requirement being about 8,000–10,000 kcal/24 h. A comparison between well fed subjects and those with food deprivation revealed significantly higher levels of (T₃) triiodothyronin, insulin and thyroid stimulating hormone (TSH) in the well-fed subjects, who also had lower levels of growth hormone (hGH) and cortisol, whereas no difference was found between the two groups for thyroxin (T₄). Increased levels were found for T₃ and T₄ in both groups during the first day of activity, with a concomitant decrease in TSH and a subsequent decrease of T₄ during the next 2 days. T₃ decreased only in the low-calory group whereas increased levels were found in the iso-calory group throughout the course. The resting levels of insulin decreased during the course in the low-calory group whereas it increased in the iso-calory group. High levels were maintained throughout the course for hGH. Cortisol showed high levels just before the start of the course and then decreased from day 2 to day 4. No difference was found between the morning and evening levels for cortisol, indicating disappearance of the circadian rhythm. The present investigation has shown that energy deficiency during prolonged physical strain is responsible for the decreased serum levels of T₃ and insulin and may contribute to the decrease in TSH and the increase in hGH and cortisol.     

Psychosocial stress and symptoms of menopause: a comparative study of menopause clinic patients and non-patients

In much of the literature to date, the definition of climacteric symptoms has been based largely upon women who present for medical treatment of symptoms. It is already well recognised that patients (of all ages and both sexes) presenting for medical treatment tend to report themselves as suffering from more life stresses and from more neurotic symptoms than people in the general population. Life stress and adequacy of coping may thus be important factors in the incidence of symptomatology at the climacteric, as at any other time of life. This study therefore investigated the proposal that post-menopausal women who present for treatment at menopause clinics suffer from more life stresses and more neurotic symptoms than post-menopausal women in the general pupolation.

It was found that patients did indeed suffer from more psychosocial stress, measured in terms of life events, clinical depression and anxiety scales and a rating scale based on a clinician's judgements of ongoing psychosocial stress, vulnerability and adequacy of coping. Patients also suffered from significantly more symptoms than non-patients, not only psychological, but also hypothalamic and metabolic symptoms. However, the incidence of hot flushes and vaginal atrophy was the same in both groups. The stress/coping rating was the measure which correlated most highly with the psychological symptoms reported by subjects as symptoms of menopause. Life events and clinical stress measures were more consistently related in the non-patient group, indicating possible intervening variables (such as hormone imbalance) in this relationship in the patient group.     

Social status constrains the stress response in the squirrel monkey.

The influence of dominance on the pituitary-adrenal and gonadal systems was evaluated in male squirrel monkeys. Basal and stress levels of plasma cortisol and testosterone were determined in eight male pairs across a 5-week period. The data indicated that squirrel monkeys have unusually high levels of steroid hormones in comparison to other species. Dominant males had higher levels of cortisol and testosterone and showed a smaller stress response than did subordinate males.     

Development of a non-invasive treatment system for urinary incontinence using a functional continuous magnetic stimulator (FCMS)

A system composed of a functional continuous magnetic stimulator (FCMS) and a saddle-type coil has been developed for non-invasive treatment of urinary incontinence, especially stress incontinence and urge incontinence. The FCMS conditions were as follows: 2 kW maximum electrical power consumption, 800 V maximum capacitor voltage, 720 μs pulsewidth (180 μs rise time), and 5–30 Hz frequency. A frequency between 5 and 10 Hz is used to treat urge incontinence and a frequency between 25 Hz and 30 Hz is used to treat urge incontinence. The coil (120 mm long, 90 mm wide and 50 mm thick) fits the most suitable region for this treatment, the region from the anus to the perineum. The coil is cooled to maintain a coil temperature between 20 and 25°C so that it can be used efficiently and safely. In experiments with anaesthetised dogs, it was confirmed that the urethral pressure increased when the circumference of the perineum received continuous magnetic stimulation of 720 μs pulsewidth (180 μs rise time), 10Hz frequency and about 520 V capacitor voltage. This result suggests that magnetic stimulation can be effective as a urinary incontinence therapy.     

人体腰椎活动节段应力分布的实验研究

本文采用三维光弹性实验方法观察了正常腰椎活动节段的应力分布。用精密浇铸,严格几何相似的光弹性环氧树脂腰椎和硅橡胶椎间盘模型进行三维光弹性实验,并观察腰椎的等应力差图和有效应力值分布。本实验观察到,腰椎椎体上下缘应力分布较均匀对称,其后缘应力大于前缘,后部结构应力较小。作者认为,三维光弹性实验方法具有直观性强,能有效和准确地确定腰椎的应力分布,对腰椎生物力学研究具有重要的实用价值。腰椎后缘应力大于前缘,使椎体后缘承载较大,将会增加腰椎间盘退变和损伤的机会,这可能是引起腰腿痛的重要因素。