1-delta9-tetrahydrocannabinol: neurochemical and behavioral effects in the mouse

Administration of pure 1-delta(9)-tetrahydrocannabinol to mice had the following dose-dependent nzeurochemical and behavioral effects: a slight but significant increase in concentrations of 5-hydroxytryptamine in whole brain; a decrease in concentration of norepinephrine in brain after administration of low doses and an increase after high doses; diminished spontaneous activity, mloderate hypothermnia, hypersetisitivity to tactile and auditory stimiuli, and ataxia after low doses; and sedation, pronounced hypothermia, and markedly diminished spon taneous activity and reactivity after high doses. The duration of the effects on body temperature and spontaneous activity correlated generally with the changes in brain amines. The characteristic changes in brain amines do not correspond exactly to those observed with other psychotropic drugs.     

Lack of tolerance to 9 -tetrahydrocannabinol in chimpanzees

Five chimpanzees were given Delta(9)-tetrahydrocannabinol (Delta(9)THC): 1.0 milligram per kilogram of body weight for 21 days and 4.0 milligrams per kilogram of body weight for 42 days. Although accuracy and speed of performance on a delayed matching-to-sample task were significantly affected by both doses, tolerance to Delta(9)THC did not develop. No long-term behavioral effects of Delta(9)THC were observed after termination of the drug regimens.     

Color-discrimination performance of pigeons: effects of reward

Performance of two pigeons given tasks in discriminating colors was examined on trials before and after they had occasionally received rewards for pecking when exposed to light of specific wavelengths. After a reward, the probability that the birds would respond to light svtimuli that were never rewarded was higher than before the reward was given, but paradoxically the birds showed no general decline in their ability to differentiate between stimuli at wavelengths 1 millimicron apart.     

Alcohol aversion in the rat: behavioral assessment of noxious drug effects

Injections of p-chlorophenylalanine or n-butyraldoxime given after rats were first given a 10-minute drinking test with saccharin or ethanol solutions produced a learned aversion to these solutions. These findings suggest that the reduced self-selection of alcohol (preference) resulting from the administration of these drugs, reported by others, is not specifically alcohol-related. The technique described offers a sensitive procedure for the assessment of unpleasant effects of drugs.     

Knockdown of ACS9 expression in Arabidopsis decreases the tolerance to salt and osmotic stress

Based on the DNA sequence of ACS9, two produced fragments were subcloned into binary vector pCAMBIA1300 in antisense and sense orientations, and the generated RNA interference (RNAi) vector was then transformed into Arabidopsis thaliana. The stress resistance function of ACS9 gene in Arabidopsis thaliana was researched by determination of stress resistance physiologic indexes, NaCl and PEG6000 resistance. The results showed that the inhibition of ACS9 expression enhanced the sensitivity to high concentration NaCl (150 mmol/L) and PEG6000 (7%) in Arabidopsis thaliana seeding stage. The proline contents and water loss rates in transgenic plants were 0.68 and 1.4 times higher than those in the wild-type leaves, respectively, indicating that the inhibition of ACS9 expression due to salt and drought resistant was reduced and suggested that ACS9 gene played important roles in plant salt and drought tolerance.     

Nutritional and environmental interactions in the behavioral development of the rat: long-term effects

The behavioral effects of early malnutrition and early environmental isolation were observed in male rats. Dietary and environmental manipulations occurred during the first 7 weeks of life, after which followed a 10-week recovery period. On the basis of several different responses, it was found that the behavioral effects of early malnutrition were exaggerated by the environmental isolation. In most cases, the behavioral effects of early malnutrition were completely eliminated by supplying "additional stimulation" early in life. Two theoretical mechanisms are proposed to explain these findings.     

Drug history modifies the behavioral effects of pentobarbital

Behavior of squirrel monkeys, maintained by the termination of stimuli associated with electric shock, was suppressed by response-dependent shock delivery. The effects of pentobarbital on this behavior depended on whether monkeys had previously received morphine. In monkeys without experience with drugs, pentobarbital increased responding. In monkeys with recent experience with morphine, however, pentobarbital resulted in a smaller increase or decrease in responding. The rate-decreasing effects of pentobarbital after a history of morphine administration could be reversed by the administration of d-amphetamine. These findings suggest that the behavioral effects of abused drugs may depend on previous experience with other drugs, even when those drugs are from a different pharmacological class.     

Stereoisomers of N-allylnormetazocine: phencyclidine-like behavioral effects in squirrel monkeys and rats

(+/-)-N-Allylnormetazocine is a benzomorphan opioid with psychotomimetic effects. The pure stereoisomers of this compound, as well as the racemic mixture, were compared to phencyclidine for their behavioral effects on squirrel monkeys and rats trained to discriminate phencyclidine from saline. Dose-response determinations were made for responses to phencyclidine, to a racemic mixture of N-allylnormetazocine, and to the pure levo and dextro isomers of N-allylnormetazocine. In both rats and monkeys, the dextro isomer and the racemic mixture produced dose-dependent responses appropriate for phencyclidine; the levo isomer did not produce the responses appropriate for phencyclidine at any of the doses tested. In both species, the levo isomer was more potent than the dextro isomer in decreasing the rate of responding. Thus racemic N-allylnormetazocine is a mixture of compounds that produce different behavioral effects.     

9 -tetrahydrocannabinol: dose-related effects on timing behavior in chimpanzee

Delta(9)-Tetrahydrocannabinol, at doses within the effective range for humans, was administered orally to chimpanzees with stable, efficient timing performances maintained by multilink chained schedules of food reinforcement. Reinforcements decreased with increasing dose, because of decreased frequencies of total operant timing responses and decreased accuracy of the timing performances which did occur. Higher doses exerted an effect for up to 3 days.     

Orientation by pigeons: is the sun necessary?

Although most recent hypotheses of pigeon homing have assigned an essential role to the sun, there has been some evidence suggesting that the sun is not essential. Two series of releases were designed to examine the question more carefully. Birds whose internal clocks had been shifted 6 hours were used in the critical tests. Under sun, the vanishing bearings of the clock-shifted birds were deflected in the direction predicted by a hypothesis of use of the sun as a simple compass. By contrast, under total overcast the bearings of both the clock-shifted and the control birds were homeward oriented and there was no difference between them, even at a release site the birds could never have seen previously. Therefore it is concluded that the sun is used as a compass when it is available, but that the pigeon navigation system contains sufficient redundancy to make accurate orientation possible in the absence of both the sun and familiar landmarks; the orientational cues used under such conditions do not require time compensation. This conclusion is in complete disagreement with the Matthews sun-arc hypothesis of pigeon navigation, and it makes necessary a major reformulation (at the very least) of the other principal hypothesis, that of Kramer.     

Requirement of hippocampal neurogenesis for the behavioral effects of antidepressants

Various chronic antidepressant treatments increase adult hippocampal neurogenesis, but the functional importance of this phenomenon remains unclear. Here, using genetic and radiological methods, we show that disrupting antidepressant-induced neurogenesis blocks behavioral responses to antidepressants. Serotonin 1A receptor null mice were insensitive to the neurogenic and behavioral effects of fluoxetine, a serotonin selective reuptake inhibitor. X-irradiation of a restricted region of mouse brain containing the hippocampus prevented the neurogenic and behavioral effects of two classes of antidepressants. These findings suggest that the behavioral effects of chronic antidepressants may be mediated by the stimulation of neurogenesis in the hippocampus.     

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.     

Delta 9-tetrahydrocannabinol: aversive effects in rat at high doses

Water-deprived rats were administered a single dose of Delta(9)-tetrahydrocannabinol either orally or intraperitoneally immediately after their first taste of a saccharine solution. In tests beginning 47 hours after drug administration, a dose-related reversal of rats' normal preference for saccharine was found. The data suggest that the drug produces aversive effects at doses of 1 to 32 milligrams per kilogram.     

Deciphering the message in protein sequences: tolerance to amino acid substitutions

An amino acid sequence encodes a message that determines the shape and function of a protein. This message is highly degenerate in that many different sequences can code for proteins with essentially the same structure and activity. Comparison of different sequences with similar messages can reveal key features of the code and improve understanding of how a protein folds and how it performs its function.     

9 -Tetrahydrocannabinol: effects on mammalian nonmyelinated nerve fibers

Delta(9)-Tetrahydrocannabinol can be applied to tissue in vitro by dissolving it in Pluronic F68 and ethanol. It causes a decrease in size of the compound action potential of the nonmnyelinated fibers of the vagus nerve of the rabbit. This effect appears to be dose-related and chloride-dependent. Effects on other measurable parameters of nerve function seem to be minimal. Although the amounts required seem to be higher than those required to produce hallucinogenic effects in man, this effect is consistent with other work on Delta(9)-tetrahydrocannabinol and may ultimately account for a significant portion of the pharmacological activity of this drug.     

The sun azimuth compass: one factor in the orientation of homing pigeons

In accordance with the theory of the sun azimuth compass (1), displaced homing pigeons are misled in a predictable way if their "internal clock" has been reset by exposure to a time-shifted sequence of day-night cycles.     

Tolerance develops to the disruptive effects of delta 9-tetrahydrocannabinol on primate menstrual cycle

Long-term exposure of sexually mature female rhesus monkeys (Macaca mulata) to thrice weekly injections of delta 9-tetrahydrocannabinol resulted in a disruption of menstrual cycles that lasted for several months. This period was marked by an absence of ovulation and decreased basal concentrations of gonadotropin and sex steroids in the plasma. After this period, normal cycles and hormone concentrations were reestablished. These studies demonstrate that in rhesus monkeys subjected to long-term treatment with delta 9-tetrahydrocannabinol tolerance develops to the disruptive effects of the drug on the menstrual cycle.     

l-Dgr9-trans-Tetrahydrocannabinol in Pigeons: Tolerance to the Behavioral Effects

Delta(9)-Tetrahydrocannabinol was injected daily, in increasing doses, in pigeons under a multiple schedule of food presentation. Within a week, a dose that initially abolished responding completely was without effect. This dose was gradually increased to 20 times its original value without disrupting the behavior. No withdrawal syndrome was detected when the cannabinol was discontinued.     

Anoxia: tolerance in reptiles

Measurements of the lengths of time various reptiles can continue to breathe in atmospheres of nitrogen have shown that turtles are several times more tolerant of these conditions than are other reptiles. The major correlate of this tolerance is taxonomic, rather than ecological.