Motivated behavior and the estrous cycle in rats

(1) The estrous cycle in the rat may be used to study recurrent changes in motor behaviors and motivation which are strongly related to cyclic hormonal and CNS changes. (2) The peak in motivated behaviors occurs during a sharply defined period on the night between proestrus and estrus and is evident in facilitated wheel-running, lordosis, and intracranial self-stimulation. (3) Behaviors without a clearly motivated character do not show an estrous cyclicity. (4) The estrous cyclic variation in intracranial self-stimulation was observed at a specific locus — the pars campacta of the substantia nigra. (5) A neurochemical link between sexually motivated behavior, wheel running and intracranial self-stimulation is suggested. This link is in part dopaminergic but is probably also activated by many other systems.     

D1 Dopamine receptor-mediated substance P depletion in the striatonigral neurons of rats subjected to neonatal dopaminergic denervation: implications for self-injurious behavior

The present study examined the influences of dopamine (DA) receptor stimulation on enkephalin (Met5-enkephalin; ME) and tachykinin (substance P; SP) systems of basal ganglia of Sprague-Dawley rats, lesioned as neonates with 6-hydroxydopamine (6-OHDA). It has been proposed that the neonatal 6-OHDA-lesioned rat could serve as a model for the DA deficiency and self-injurious behavior (SIB) observed in the childhood neurological disorder. Lesch-Nyhan syndrome. In agreement with earlier work, the present study found that the neonatal 6-OHDA treatment at 3 days of age, reduced DA and caused an increase in ME and a decrease in SP content in the striatum and substantia nigra, when tested as adults. Administration of the DA precursor, L-dihydroxyphenylalanine (L-DOPA), to lesioned animals, induced SIB; increased DA and DOPAC levels; produced a greater decrease (-64%) in SP levels in the striatum and substantia nigra than was observed with lesion alone (-28%). The L-DOPA-induced decrease in SP levels and the SIB observed in the lesioned animals were blocked by pretreatment with the D1 receptor antagonist, SCH-23390. Moreover, administration of the D1 receptor agonist, SKF-38393, but not the D2 agonist, LY-171555, to lesioned animals mimicked the L-DOPA responses in all respects, except that the agonists did not alter DA or DOPAC levels. None of the DA agonists or antagonists treatments affected lesion-induced increase in ME levels in the striatum. These results indicate for the first time, that SIB precipitated by DA agonists in neonatal dopaminergic denervated animals, is associated with a marked and selective decrease in SP in the striatonigral SP neurons. This process has two components: (a) a retarded development of the SP system due to neonatal dopaminergic denervation: and (b) a depletion of the remaining SP, presumably by enhanced release due to D1 DA receptor-mediated activation of striatonigral SP neurons.     

Differential mechanisms involved in the anticonflict action of benzodiazepines injected into the central amygdala and mammillary body

The present study was designed to clarify the mechanism of action of benzodiazepines (BDZ) injected into the central amygdala (ACE) and mammillary body (MB). When gamma-aminobutyric acid (GABA) at doses of 30 and 70 micrograms, muscimol (0.01 and 0.03 microgram), valproate (200 micrograms), atropine (20 micrograms) and cyproheptadine (3 micrograms) were bilaterally injected into ACE, a significant and marked increase in the punished responses of conflict schedule was observed. These drugs injected into MB failed to increase the punished responses. In MB, only noradrenaline (NA, 20 micrograms) showed the anticonflict action. NA 20 micrograms also produced the anticonflict action in ACE. These results suggest that the mechanism of anticonflict action of BDZ is different in brain areas. The GABA-ergic, cholinergic, serotonergic and NA-ergic systems seem to be involved in the mechanism of anticonflict action of BDZ in ACE. While the NA-ergic system appears to be operative in MB.     

8—2岁市区学龄儿童感觉统合失调与不良行为及家庭因素调查分析

目的：调查本市区小学儿童感觉统合失调现状与不良行为及家庭因素的关系。方法：用感觉统合诊断量表和自制儿童生长发育调查表对1775名学龄儿童进行心理行为问题调查。结果：感觉统合轻度失调23．4％，重度失调13．5％，男童失调发和率（42．86％）明显高于女童（31．36％）P＜0．0），前庭功能失衡发生率最高（21．30％）；统合失调组儿童不良行为发生率高达64．38％明显高于统合正常组（31．11％）P＜0．01，失调组不良行为各因子的发生率亦明显高于统合正常组P＜0．01；学习能力不足儿童与父母文化程度和不同职业有关P＜0．01。结论：儿童感觉纺合失调现状易成为成人心理障碍的潜在因素，应引起重视。     

Sex effects in defensive behavior: Baseline differences and drug interactions

Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.     

铁叶绿酸钠对小鼠行为发育毒性的实验研究

铁叶绿酸钠为叶绿素衍生物,研究表明铁叶绿酸钠治疗妊娠期缺铁性贫血,疗效显著。由于妊娠期用药可能对子代产生行为发育毒性,因此本文重点针对铁叶绿酸钠在动物围产期用药后,可能对子代动物的神经行为发育产生的毒性进行了测试,试验结果表明在高、中、低三种剂量下其对子代小鼠无明显行为发育毒性。     

Mechanical Testing of Seven Fixation Methods for Generation of Compression Across a Midtarsal Osteotomy: A Comparison of Internal and External Fixation Devices

The purpose of this study was to assess 7 methods of fixation for a midtarsal osteotomy. Polyurethane foam models (N = 6) and cadaver specimens (N = 4-7) were used to examine the force generated by the different constructs of fixation. A midtarsal osteotomy was performed on each specimen in the test groups. The osteotomies were fixated either with 2 parallel 0.062-in Kirschner wires and 40-mm-long, 4-mm partially threaded, cancellous, cannulated titanium screws, an external ring fixator (frame), a frame with wires tensioned (tension), a frame with wires tensioned and compressed toward the osteotomy (tension and compression), a frame with tension, compression, and parallel Kirschner wires, or a frame with tension, compression, and two 4.0 cannulated parallel screws, respectively. Each model was fixated, and the force generated by the construct across the osteotomy was recorded via the use of pressure-sensitive film. Statistical analysis of the data in the polyurethane foam group determined that the use of frame with tension, compression, and two 4.0 parallel cannulated screws was statistically superior to 1) frame, 2) frame with tension, 3) 2 parallel Kirschner wires, 4) two 4.0 cannulated parallel screws, and 5) frame with tension and compression. A cadaver study determined that the frame with tension, compression, and 2 parallel Kirschner wires was statistically superior to 1) frame and 2) two parallel Kirschner wires. These findings suggest that there is a difference in the force generated by the type of fixation construct across a midtarsal osteotomy.     

停止尿床年龄与青少年自杀行为的关系

目的探讨停止尿床年龄与青少年自杀行为的关系。方法对1920名11岁～16岁的青少年进行调查,由父母完成包括青少年生长发育史、自杀行为、抑郁症状、攻击行为及家庭环境等定式问卷。结果在控制一系列儿童及家庭情况变量后,多变量Logistic回归模型显示3岁后停止尿床与青少年自杀行为的危险性增加显著相关,停止尿床年龄与青少年自杀行为之间存在量效关系（3岁～4岁停止尿床OR值为2.1,5岁及以上停止尿床OR值为3.6）。中介变量分析显示,停止尿床时间晚对自杀行为的效应,至少部分通过抑郁及攻击行为中介。结论停止尿床时间晚可能是青少年自杀行为的早期神经发育预测因素,应进一步探讨青少年自杀行为的早期神经发育危险因素及潜在机制。