The Effects Of Delta-9-tetrahydrocannabinol Research Articles

The effects of delta 9-tetrahydrocannabinol alone and in combination with cannabidiol on fixed-interval performance in rhesus monkeys.

It has been reported that cannabidiol (CBD) antagonizes the effects of delta 9-tetrahydrocannabinol (THC) on operant behavior in rats and pigeons. We have replicated this finding with rhesus monkeys. Four rhesus monkeys were trained to lever press on a fixed-interval 5-min schedule of food presentation with a 1-min limited hold and 1-min time out between successive intervals. The effects of 0.3 and 1.0 mg/kg THC alone were determined three times during the experiment; before the CBD-THC interaction, after the CBD-THC interaction and once with the CBD vehicle. A dose of 30 mg/kg CBD, which alone resulted in a 24% reduction in responding, completely antagonized the response rate reduction produced by 0.3 mg/kg THC. The effects of THC revealed a rate-dependent effect that did not conform to the log-linear rate-dependency plots described for most other drugs.

Effect of delta 9-tetrahydrocannabinol on the morphine-induced hyperactivity of mice.

The effect of delta 9-tetrahydrocannabinol (THC) on the locomotor activity-stimulating action of morphine has been investigated in mice. THC (10 mg/kg) has been found to potentiate morphine-induced hyperactivity. On the other hand, the stimulating action of morphine on motor activity strongly diminished in mice rendered tolerant by the implantation of a morphine pellet. The pretreatment of morphine-tolerant mice with the same dose of THC did not change the effect of morphine on the motor activity. These results suggest that tolerance also developed to the potentiating action of THC on morphine-induced hyperactivity during the development of tolerance to this action of morphine.

Interaction of ambient temperature with the effects of ? 9 on brain catecholamine synthesis and plasma corticosterone levels

The effects of delta 9-tetrahydrocannabinol (THC) on body temperature, catecholamine synthesis and plasma corticosteroid levels were examined in the mouse at ambient temperatures of 31 degrees, 20 degrees and 10 degrees C in order to study the role of hypothermia in the THC's other actions. THC produced hypothermia at 10 degrees and 20 degrees C, but not at 31 degrees C. Dose related increases in dopamine and norepinephrine synthesis rates and plasma corticosterone levels were produced by THC at both 31 degrees and 20 degrees C. The effects of THC at 10 degrees C were biphasic. These data indicate that the effects of THC on brain catecholamines are not a result of drug induced hypothermia and may be a result of a direct action on neurons.

Effects of Δ9-Tetrahydrocannabinol Administration on Gonadal Steroidogenic Activity in Vivo

The effects of delta 9-tetrahydrocannabinol (THC) administration on gonadal steroidogenic activity in vivo were studied in two animal models: (1) luteal function of the rhesus monkey and (2) periovulatory steroid concentrations of rabbits treated with human chorionic gonadotropin (hCG). THC-treated monkeys demonstrated progesterone concentrations and luteal phase lengths which were not different from those in untreated controls. THC did not impair the normal pattern of response of the corpus luteum to increasing doses of hCG as measured by serum progesterone concentrations and luteal phase lengths. Rabbits treated with THC manifested normal periovulatory steroidal patterns (progesterone, testosterone, and dihydrotestosterone). These data suggest that THC does not significantly inhibit steroidogenesis by a direct action on the ovary. Its effect may be mediated by a central mechanism of action.

Delta 9-tetrahydrocannabinol: Elevation of absolute visual thresholds of rabbits

The effect of Delta 9-tetrahydrocannabinol (THC) on the ability of rabbits to detect a minimal light stimulus (absolute visual threshold) was examined using the method of limits with an aversive classical conditioning paradigm. Both of two dosage levels of THC, similar to an amount ingested by a human from a single cigarette, significantly elevated the absolute visual threshold of all animals. Normal baseline thresholds, however, returned with 24 hours.

The attenuation of delta 9-tetrahydrocannabinol and morphine of the quasi-morphine withdrawal syndrome in rats.

The effect of delta 9-tetrahydrocannabinol (THC), morphine, haloperidol and chlordiazepoxide on the exhibition of the signs of the quasi-morphine withdrawal syndrome was studied in rats. In preliminary studies approximately equi-sedative doses of these drugs were chosen. Morphine and THC produced a very similar degree of suppression of the signs of the quasi-morphine withdrawal, but unlike morphine, the effects of THC were not reversed by the narcotic antagonist, naloxone. The dopamine receptor antagonist, haloperidol, produced a moderate suppression of the withdrawal syndrome and chlordiazepoxide was without significant effect. It is concluded that THC is of very similar potency to morphine in suppressing the quasi-morphine withdrawal syndrome, but its activity in this regard does not appear to be dependent upon the availability of opiate or dopamine receptors, nor is it due to sedation alone.

Interaction between delta 9-tetrahydrocannabinol and morphine on the motor activity of mice.

The present experiments dealt the effects of delta 9-tetrahydrocannabinol (THC) on the locomotor activity stimulating action of morphine in mice. In the first series of experiments, the pretreatments of mice by THC in doses up to 20 mg/kg have been found to potentiate the morphine-induced hyperactivity in dose-dependent manner, but higher doses of THC did not produce such an action. In the second series of experiments the dose-response curve of morphine for the motor activity has been found to shift to the left by the pretreatment of mice with 10 mg/kg of THC. These results show a synergism between morphine and THC and suggest that both drugs may share some common site of action.

ETHANOL AND Δ 9 ‐TETRAHYDROCANNABINOL INTERACTIVE EFFECTS ON HUMAN PERCEPTUAL, COGNITIVE AND MOTOR FUNCTIONS. II

Fifteen paid student volunteers (10 male, five female) were used in a double-blind crossover experiment to further investigated the effects of delta9-tetrahydrocannabinol (THC), alone and in combination with ethanol, on perceptual, cognitive and motor functions. Both ethanol (0-54 g/kg) and THC (15 MG/70 KG) WERE GIVEN ORALLY. Ethanol was not very effective in in+uencing performance but this dose of THC produced marked decrements, predominantly in the latter part of the experiment. When they were given together, an early additive effect was apparent, but later, there was a suggestion of antagonism in that subjects who received the drug combination performed better than those who were given THC along. The interaction between THC and ethanol was considered to be complex.