Heart rate changes after reinforcing brain stimulation in rats

Cardiac responses to hypothalamic and septal stimulation are polyphasic, the first component being accelerative. As interstimulus intervals are decreased, only accelerative components appear, but prestimulus heart rates ("background levels") are decreased upon septal and are either increased or unchanged upon hypothalamic stimulation. The suggestion that parasympathetic responses accompany reinforcing brain stimulation was not supported.     

Ribonucleic acid: effect on conditioned behavior in rats

Acquisition of a behavioral response motivated by shock was enhanced in rats chronically treated with yeast ribonucleic acid, and resistance to extinction was greater in rats so treated than in controls. This extends the role of ribonucleic acid to include a behavioral effect in laboratory mammals treated with a purified preparation from yeast.     

Stress-induced suppression of immunity in adrenalectomized rats

Stress-induced suppression of lymphocyte stimulation by phytohemagglutinin was demonstrated in Isolated lymphocytes and in cultures of whole blood from adrenalectomized rats. The results demonstrate that corticosteroid independent mechanisms participate in the suppression of lymphocyte function by stressors. Stress-induced lymphopenia, however, was found to be adrenal dependent, indicating that the modulation of immunity by stress is complex and multidetermined.     

Heart rate: differential effects of hypothalamic and septal self-stimulation

Heart rate in rats was recorded during self-stimulation with electrodes permanently implanted in both the hypothalamus and the septal region. Acceleration was observed during stimulation of the hypothalamus, and deceleration during stimulation of the septal region. In both areas self-stimulation reduced variability in heart rate.     

Sodium bicarbonate: increase in survival rate of rats inhaling oxygen

The injection daily of 50 milliters of 0.15M sodium bicarbonate per kilogram of body weight significantly decreased the mortality rate of rats inhaling 95-to 98-percent oxygen. This treatment did not prevent the occurrence of degenerative changes in the germinal epithelium of the tests.     

红江橙留树保鲜的保果率及糖、酸含量动态变化

以红江橙成年树为试材,在果实转色前1个月开始进行单独的叶面喷雾GA3、土壤施氮肥和树盘覆盖地膜或其混合等5种留树保鲜处理,以期探讨其果实保果率、糖、酸含量在保鲜期间的动态变化特点.试验结果表明:5种果实留树保鲜处理均可达到良好的保果效果;不同果实留树保鲜处理的果实果糖、葡萄糖、蔗糖含量动态变化呈单峰曲线,高峰出现在处理后42 d;不同留树保鲜处理的果实酸含量在处理后42 d前快速下降,至处理后42 d达最低,之后变化趋于平缓;在12月下旬至翌年1月中旬,不同留树保鲜处理的果实可溶性糖含量较高、糖酸比适宜,建议此期作为留树保鲜处理的最佳采果期.     

Brain hyaluronidase: changes in activity during chick development

Development of embryonic chick brain is characterized by high levels of hyaluronidase activity and of hyaluronate, both of which decrease rapidly soon after the chick hatches. By analogy to other systems, it is proposed that the sequence of hyaluronate production and its enzymatic removal may have a developmental role in brain formation.     

Hemoglobin: molecular changes during anuran metamorphosis

Anuran metamorphosis is accompanied by changes in the sedimentation patterns of the lysates of red blood cells of several species. Rana grylio and Rana catesbeiana tadpoles have hemoglobins that sediment at 4.3S (molecular weight, 68,000) and gradually produce a heavier 7.0S component (estimated molecular weight, 136,000) during metamorphosis to the adult frog. There is extensive change in the amino acid compositions of these hemoglobins; these changes may account for observed changes in electrophoretic mobility.     

Dimethyl sulfoxide: lens changes in dogs during oral administration

Oral administration of dimethyl sulfoxide to young dogs reduces relucency of the lens cortex, causing the normal central zone of lens to act as a strong biconvex lens.     

红砂的净光合速率与蒸腾速率的日变化特征

以野生红砂(Reaumuria soongorica)为研究对象,在2004年5~7月早7∶00~晚20∶00(晴天)测定其净光合速率(Pn)、蒸腾速率(E)、光合有效辐射(PAR)、大气温度(T)等指标.结果表明:红砂的净光合速率日变化曲线呈M型,有明显的“光合午休”现象;红砂的蒸腾速率日变化曲线也呈M型,但“午休”现象不明显;有效光合辐射对红砂的净光合速率影响较大,大气温度则对红砂的蒸腾速率影响较大.     

Activation of lordotic responding in female rats by suppression of serotonergic activity

After systemic administration of several serotonergic antagonists, female rats that had been ovariectomized, adrenalectomized, and estrogen-primed showed lordotic responding. Lordosis could also be elicited after direct placement of serotonergic receptor blockers into hypothalamic sites known to contain serotonergic terminals. None of the treatments activated the soliciting component of the estrous behavior pattern of the female rat. It is postulated that the hypothalamus contains serotonergic terminals which suppress lordotic responding.     

Morphine: conditioned increases in self-administration in rhesus monkeys

Operant responding in three monkeys was maintained by intravenous presentations of morphine. Nalorphine produced reliable increases in morphine-reinforced responding. With successive daily nalorphine injections there was a decreased latency of self-administration responding for morphine, and substituted saline injections produced conditioned increases in morphine-reinforced responding.     

Cardiac rate regulated by nutritional factor in young rats

Milk fed by stomach tube to 2-week-old rats separated from their mothers without feeding for 16 hours transiently but fully reversed the decrease in cardiac rate which had occurred during separation. This effect was rapid in onset and was related to dosage; it was not dependent upon gastric distention, but did depend upon beta-adrenergic transmission.     

Slowing of heart rate after septal self-stimulation in rats

Heart rate, recorded continuously from rats trained to press a bar for intracranial electrical stimulation of their septal areas, fell consistently after brain stimulation. Interpretation of the rewarding effect of septal stimulation had previously been limited by the absence of any data on the autonomic effects of the stimulation. The results of this study suggest that the rewarding effect may possibly be produced by a parasympathetic (quieting) reaction of the autonomic nervous system to septal stimulation.     

Fat changes during adolescence

Lower thoracic fat, as measured on serial chest plates of 259 children in Ohio, increased in girls, between ages 6.5 and 14.5 years and, in boys, between ages 6.5 and 11.5 years. No evidence for a marked loss of "baby" fat in adolescence or for "waves" of fattening around the time of puberty was found.     

Postprandial changes in the exhalation rate of radon produced in vivo

The rate of exhalation of radon by persons with long-standing radium burdens increases about twofold shortly after a meal. The increase is short-lived and "normal" values are regained in 1.5 to 2 hours. The effect may account in part for the poor reproducibility in estimates of the freely emanating part of the radium content.     

Deafferentation in monkeys: effect on conditioned grasp response

A preliminary technique was developed for conditioning grasp response in monkeys, for use in studying the effect of damage to the central nervous system on skilled movement. That subjects were able to learn this response with a deafferented hand, in the absence of vision, indicated that purposive movements of the distal musculature are less under the control of peripheral feedback than had been generally believed.     

Membrane potential changes during chemokinesis in Paramecium

Intracellular recordings show that (i) paramecia hyperpolarize slightly in attractants and depolarize in repellents that depend on the avoiding reaction (an abrupt change of swimming direction), and (ii) paramecia more strongly hyperpolarize in repellents and more strongly depolarize in attractants that depend on changes of swimming velocity. These membrane potential changes are in agreement with a hypothesis of membrane potential control of chemokinesis in Paramecium.