Catecholamine uptake in cerebral cortex: adaptive change induced by fighting

Kinetics of the catecholainine uptake process in brain were altered by fighting. Significant increases in the apparent Michaelis constant (Km) for the uptake of norepinephrine into cerebral cortical homnogenates and significant increases in the inhibition constant (Ki) for d-amphetamnine inhibition of this uptake occurred in group-caged mice living under chronic attack from aggressive cage mates. Also, significant increases in the apparent Km and maximum velocity (Vmax) for norepinephrine uptake were observed 18 to 20 hours after the last of a series of short intense daily fights between male mice previously made aggressive by long-term individual caging. These results suggest that the natural stress of fighting leads to (i) lowered affinity for reuptake of norepinephrine into nerve endings of the cerebral cortex, (ii) an increase in the number of uptake sites, and (iii) lowered affinity for d-amphetamine.     

Increased Turnover of Cerebral Norepinephrine during Rebound of Paradoxical Sleep in the Rat

Changes in turnover of cerebral norepinephrine, as measured after intracisternal administration of the H(3) amine, have been studied in rats during selective paradoxical sleep deprivation and its following rebound. Experiments were performed under neurophysiological control. A marked increase of turnover of norepinephrine is associated with the augmentation of paradoxical sleep characteristic of the rebound period.     

Deficits in feeding behavior after intraventricular injection of 6-hydroxydopamine in rats

Intraventricular injections of 6-hydroxydopamine produced 95 percent depletion of telencephalic norepinephrine and 62 percent depletion of striatal dopamine in rats. Treated rats maintained body weight at subnormal levels and failed to increase food intake in response to a short-term decrease in glucose utilization. After treatment with the monoamine oxidase inhibitor pargyline, 6-hydroxydopamine produced no further norepinephrine depletion but increased the dopamnine depletion to 95 percent and produced complete aphagia. These effects are comparable to events that follow bilateral electrolytic lesions of the lateral hypothalanmus.     

Skin color and nutrient photolysis: an evolutionary hypothesis

Human populations native to areas of intense sunlight tend to be heavily melanized. Previous explanations for this relationship have invoked only weak selective pressures. To test the hypothesis that dark pigmentation may protect against photolysis of crucial light-sensitive vitamins and metabolites by ultraviolet light, folate was used as a model. It was found that exposure of human plasma in vitro to simulated strong sunlight causes 30 to 50 percent loss of folate within 60 minutes. Furthermore, light-skinned patients exposed to ultraviolet light for dermatologic disorders have abnormally low serum folate concentrations, suggesting that photolysis may also occur in vivo. Deficiency of folate, which occurs in many marginally nourished populations, causes severe anemia, fetal wastage, frank infertility, and maternal mortality. Prevention of ultraviolet photolysis of folate and other light sensitive nutrients by dark skin may be sufficient explanation for the maintenance of this characteristic in human groups indigenous to regions of intense solar radiation.     

Alcohol drinking: abnormal intake caused by tetrahydropapaveroline in brain

Tetrahydropapaveroline (THP), a dopamine-dopaldehyde condensation product, was delivered directly into the cerebral ventricle of rats automatically every 15 minutes for 12 days. The animals were given access to both water and ethylalcohol, the latter being presented in 12 concentrations from 3 to 30 percent. Within 3 to 6 days of the start of the infusion of THP, the rats, which normally rejected alcohol, drank alcohol solutions in increasingly excessive amounts; this was accompanied by symptoms that were similar to those of withdrawal and intoxication. These results provide evidence that an abnormal metabolite in the brain may produce the addictive state caused by alcoholic beverages.     

Biosynthesis of norepinephrine in isolated canine heart

Radioactive dopamine was injected into the blood that was perfusing an isolated heart preparation. Analysis of the norepinephrine obtained from the heart 1 hour later demonstrated that it contained radioactivity. Between 1.4 and 10.8 percent of the norepinephrine present had been formed from the dopamine. The turnover of norepinephrine was substantially higher in the ventricles than in the atria.     

Behavioral response rates in pigeons: effect of alpha-methyl-m-tyrosine

An intramuscular injection of alpha-methyl-m-tyrosine ( 100 mg/ kg), which differentially depletes serotonin and norepinephrine in both brain and heart, was given to two groups of pigeons trained to peck at a key for food. The first group received an injection 12 hours before the daily session and showed no behavioral effect. Response rates of birds in the second group, which were injected 30 minutes after the start of the daily session, decreased and returned to normal within 9 hours after injection. Preliminary data on brain serotonin of pigeons indicate that the disruption of the behavior follows the same time course as the change in serotonin.     

大黄酸对脑缺血再灌注小鼠脑组织内NO的影响

目的研究大黄酸（Rhein）对脑缺血再灌注小鼠脑组织内NO含量的影响。方法采用昆明种小鼠,随机分为5组：假手术组,模型对照组,大黄酸大、中、小剂量组。采用改良的Himori法制备小鼠全脑缺血5min再灌注30min模型。脑缺血前30min腹腔注射给药。再灌注后断头取脑,低温制备10％的脑组织匀浆,测定脑内NO的含量。观察不同剂量大黄酸对缺血再灌注小鼠脑内NO的含量的影响。结果各组之间的小鼠的呼吸次数没有明显的差异,小鼠呼吸的持续时间假手术组、大黄酸组与模型组比较差异有显著性（P〈0．05或P〈0．01）;不同剂量的大黄酸对缺血小鼠脑内NO的含量有不同的影响,中剂量大黄酸使小鼠脑内NO量明显减少,大剂量次之,小剂量的大黄酸对脑内NO的影响最小。结论合适剂量的大黄酸对小鼠脑缺血再灌注过程中升高的NO有降低作用,从而缓解NO导致的神经毒性作用,发挥保护缺血性脑损伤的作用。     

Neuronal perikarya of rat brain isolated by zonal centrifugation

Cerebral cortex and hippocampus of rat were disrupted in a specially designed tissue-press and prepared as a 2 percent suspension in 10 percent buffered Ficoll medium and fractionated by density-gradient centrifugation in the B XIV zonal rotor. The suspension was injected into a buffered 30 percent Ficoll, 58 percent sucrose discontinuous gradient previously loaded in the B XlV zonal rotor spinning at 3500 revolutions per minute. Intact neuronal perikarya were recovered as a discrete band in the dense sucrose zone of the gradient after centrifugation at 35,000 revolutions per minute for 45 minutes.     

Supernova remnant w-44: observations at 8350 megacycles per second

The region of W-44 was mapped at 8350 megacycles per second. The degree of linear polarization of the most intense portion of W-44 integrated over the 10.8-minute-of-arc beam was 11+/-2 percent at position angle 45 degrees +/-5 degrees . This high degree of polarization is further evidence that W-44 is a supernova remnant. The integrated flux density of (95+/-25) x 10(-26) watt per square meter per cycle per second for this source is consistent with measurements at lower frequencies extrapolated with the use of a spectral index of-0.44, obtained by other observers. In addition, the compact source 3 minutes of right ascension west of W-44 was unpolarized, within the error of measurement. The flux density of (23+/-6)x 10(-26) watt per square meter per cycle per second determined for it along with the results of other observers indicate that this source has a thermal spectrum.     

A strong influence of serotonin axons on beta-adrenergic receptors in rat brain

The role of serotonin axons in modulating the norepinephrine neurotransmission system in rat brain was investigated. Selective lesions of the forebrain serotonergic system were made by injecting 5,7-dihydroxytryptamine into the midbrain raphe nuclei. Four to six weeks after the lesion, the uptake of 3H-labeled serotonin in the frontal cortex and the hippocampus was reduced by more than 90 percent, while neither the uptake of 3H-labeled norepinephrine nor the content of norepinephrine was affected in either tissue. The number of beta-adrenergic receptors, as measured by radioligand binding with 3H-labeled dihydroalprenolol, was increased in the frontal cortex and hippocampus of rats with lesions. Similarly, specific lesions of central serotonin axons produced by systemically administered p-chloramphetamine resulted in an increase in the binding of 3H-labeled dihydroalprenolol to beta-adrenergic receptors and in the production of adenosine 3',5'-monophosphate in response to isoproterenol. These results indicate that serotonin axons may regulate beta-adrenergic receptor number and function in brain.     

Uptake of tritium-labeled norepinephrine in brain and other tissues of cat in vitro

Slices of cat cerebral cortex, heart, and spleen that have been incubated in media containing approximately 5 to 25 mmicrog of dl-norepinephrine-7H(8) per milliliter contain levels of isotopic amine greater than those in the medium. The effects of norepinephrine concentration, reserpine, and ouabain on the uptake suggest that the amine enters cells both by diffusion and by a concentrating miechanism that is saturated at low levels of norepinephrine. The drugs inhibit the latter.     

Histochemical fluorescence after application of neurochemicals to caudate nucleus and septal area in vivo

The movement of carbachol, norepinephrine, and dopamine from cannula sites in caudate nucleus and septal area of freely moving rats was traced by means of biogenic amine fluorescence. Fluorescent patterns seen after application of carbachol and norepinephrine to brain tissue did not appear to differ from controls. Three types of movement from the cannula site after administration of dopamine were observed. There was a spherical distribution approximately 2 millimeters in diameter. Fluorescence also followed axonal pathways in the orthodromic direction, suggesting that dopamine may have been transported by " axonal streaming " or by some other unknown mechanism in periaxonal spaces. Because fluorescence was present in both the ependymal lining and the choroid plexus, it was inferred that the cerebral ventricles were also involved in the movement of chemical. Any attempt to ascribe anatomical localization to behavioral effects resulting from chemical stimulation of the brain should take into account the widespread movement of chemicals after their local application to brain tissue.     

Relationship of stress-induced histidine decarboxylase to circulatory homeostasis and shock

Histidine decarboxylase activity of mouse tissues is increased by stress and by injection of epinephrine and norepinephrine, suggesting a balance between histamine and catechol amines producing a component of circulatory homeostasis. Imbalance during intense stress might lead to failure of circulatory homeostasis and to shock. Reasons for discounting histamine as "shock toxin" may be invalid.     

Memory impairment after subcutaneous injection of acetoxycycloheximide

Subcutaneous injection of 240 micrograms of acetoxycycloheximide in mice rapidly produces marked inhibition of cerebral protein synthesis. Treated mice were trained to escape shock by choosing the lighted limb of a T-maze. When trained five or more minutes after injection, they had a normal capacity to learn. They remembered normally 3 hours after training, but 6 hours after training they had markedly impaired retention. Amnesia persisted thereafter. Injections immediately after training had a less marked but significant amnesic effect. These studies suggest that protein synthesis is not necessary for learning or for memory for 3 hours after training but that it is required for long-term memory. The protein synthesis which appears to be necessary for long-term e3memory occurs during training, or within minutes after training, or both.     

Pharmacologic effects in man of a specific serotonin-reuptake inhibitor

Fluoxetine (Li-ly 110140) caused a 63 percent inhibition of [3H]serotonin uptake into platelets obtained from normal volunteers to whom the drug was administered daily for 7 days. This dose had no effect on the usual pressor response produced by injections of norepinephrine or tyramine.     

Neurochemical correlate of a spatial preference in rats

Spatial (left or right) preferences were determined for rats given foot shock in a T-maze. The animals were killed, and left and right striata were assayed separately for dopamine and left and right teldiencephalic regions were assayed for norepinephrine. Dopamine content was significantly higher (by 12 percent) in the striata contralateral to rats' side preferences than in the ipsilateral striata; there was no such difference for teldiencephalic norepinephrine. The small asymmetry in striatal dopamine content is not due to any learning- or stress-related change induced by the testing procedure but is probably inherent in normal rats. Some spatial behavior appears to be the manifestation of a normal and specific difference in the activity of left and right nigrostriatal systems.     

Brain serotonin concentration: elevation following intraperitoneal administration of melatonin

The intraperitoneal administration of melatonin to rats caused an increase in brain serotonin concentration, especially in the midbrain. This effect could be demonstrated within 20 minutes of melatonin administration and was not associated with changes in norepinephrine concentration.     

Infrasound at long range from saturn v, 1967

Two distinct groups of infrasonic waves from Saturn V, 1967, were recorded at Palisades, New York, 1485 kilometers from the launch site. The first group, of 10-minute duration, began about 70 minutes after launch time; the second, having more than twice the amplitude and a duration of 9 minutes, commenced 81 minutes after launch time. From information on the Saturn V trajectory and analysis of recorded data, it is established that the first group represents sound emitted either by the first stage reentry or by the second stage when its elevation was above 120 kilometers. The second, more intense wave group represents the sound from the powered first stage. A reversal of signal occurs because the rocket outran its own sound. Fourier analyses indicate that the energy extends to relatively long periods-10 seconds for the first stage and 7 seconds for the second. Trapping of sound in the upper atmospheric sound channel can be the cause of the separation of the signal into two distinct groups.     

L-dihydroxyphenylalanine: effect on S-adenosylmethionine in brain

Forty-five minutes after intraperitoneal injection of a single dose (100 milligrams per kilogram) of L-dihydroxyphenylalanine, the concentration of S-adenosylmethionine in rat brain was lowered by 76 percent. As little as 10 milligrams of L-dihydroxyphenylalanine per kilogram decreased content of S-adenosylmethionine in the adrenal medulla by 51 percent, whereas 100 milligrams per kilogram did not significantly depress concentration of S-adenosylmethionine in the liver in this time interval. Concentration of S-adenosylmethionine in the brain varied diurnally; L-dihydroxyphenylalanine lowered this concentration whether administered at the daily peak or at the nadir.