Effect of subchronic treatment with (−) δ8-trans-tetrahydrocannabinol (δ8-THC) on food intake,body temperature,hexobarbital sleeping time and hexobarbital elimination in rats

In a series of experiments in rats it was possible to prove that ⁸-THC has the same type of effectiveness as the stereo-isomeric ⁹-THC.Body temperature was reduced to 35.5 C 90 min after injection of 10 mg/kg ⁸-THC; 5 mg/kg ⁸-THC extended the duration of hexobarbital sleeping time from 119 min in control animals to 205 min. Following treatment with ⁸-THC for 9 and 10 days the effects on hypothermia and prolongation of sleeping time were less pronounced than in acute experiments. Body temperature dropped to 36.4 C 90 min p.i. and the duration of hexobarbital sleeping time was only extended to 156 min. This attenuation of effects after subchronic THC treatment was regarded as due to the development of tolerance.In order to exclude the possibility that the extension of sleeping time might be due to an effect of THC on hexobarbital metabolism, the hexobarbital concentration in cerebral tissue and blood was determined 30, 60, 90 and 120 min after the administration of 100 mg/kg hexobarbital-Na. There was no difference in hexobarbital elimination between rats treated with THC in a single dose or over a 10-day period and control animals.We are indebted to the Bundesministerium für Jugend, Familie und Gesundheit for financial support.     

Effects of (−)δ9-trans-tetrahydrocannabinol (δ9-THC) on memory,attention and subjective state

In a double blind study, cross-over design, on 37 volunteers several effects of an orally administered dosage of 15 mgs (–)- ⁹-trans-tetrahydrocannabinol ( ⁹-THC) were assessed. The results did bear out the hypotheses of this experiment that the impairment of attention and information storage in the long-term memory as well as depersonalization and temporal disintegration phenomena induced by ⁹-THC are interrelated. Furthermore, the sequence of information retrieval from memory was found to be changed by ⁹-THC.     

Toxicologic studies of a superpotent α-melanotropin, [Nle4, D-Phe7]α-MSH

Summary A toxicology study was performed in mice given a superpotent melanocyte stimulating hormone (MSH) analog. This 13 amino acid derivative, [Nle⁴, D-Phe⁷]-MSH or NDP-MSH, is a melanotropin which is very slowly biodegraded in vivo and is active at 1/1,000 the concentration of natural -MSH. Mice were administered up to 2 mg/kg of the analog daily and weekly over 4 or 12 weeks by both topical application (in 90% DMSO) or by IP injections (in physiologic saline). At the end of this period, no toxic effects were observed in various organs, on hematologic indices, or on weight gain. A slight increase in triglyceride and platelet levels were noted in mice given the analog weekly for 12 weeks. There was no evidence of an effect on behavior nor ACTH-like endocrine actions such as elevated serum cortisol levels. Transdermal drug delivery studies performed in vitro showed reproducible diffusion of the NDP-MSH analog through full-thickness mouse skin. Approximately 0.002% to 0.05% of a 10^–4M preparation was transdermally delivered using a DMSO/water solution or a PEG/alcohol cream base, respectively. This superpotent analog is now entering a Phase I clinical trial with possible therapeutic applications for the treatment of hypomelanotic disorders such as vitiligo and for pharmacologic tanning without the need for sunlight exposure.     

Effects of Δ1(2)-tetrahydrocannabinol on copulation in the male rat

The mating behavior of 15 male rats was measured after treatment with ¹⁽²⁾-tetrahydrocannabinol (THC) and propylene glycol (vehicle). Administration of either 2 mg per kg or 3 mg per kg body weight of THC was followed by significant increases in latency to the first mount, latency to ejaculation, and latency to the first mount following ejaculation. No significant changes were found in the number of intromissions or mounts. The deterioration in sexual performance is interpreted as reflecting a decreased motivation to copulate under the influence of the drug.     

Effects of Δ9-Tetrahydrocannabinol (THC) and chlordiazepoxide (CDP) on state-dependent learning: evidence for asymmetrical dissociation

⁹-Tetrahydrocannabinol (THC) and chlordiazepoxide (CDP) were studied for their effects upon acquisition, performance, state-dependent learning and reciprocal substitution in mice. Over a wide dose range, CDP had no effect while THC had a biphasic effect (depression at low doses and facilitation at high doses) on avoidance acquisition. Both agents elicited evidence for state-dependent learning; mice trained under drugged conditions failed to transfer learning to the non-drugged state. In contrast, performance decrements occurred only after high doses (40 mg/kg) of each were given to avoidance trained mice. Administration of CDP facilitated avoidance performance in drug naive mice after doses of 1.25 mg/kg and above. THC failed to prevent learning deficits in CDP-trained subjects. In contrast, CDP prevented avoidance deficits after doses of 5 mg/kg and above in THC-trained subjects. These results suggest that an asymmetrical dissociation exists between THC and CDP or between either agent and saline.Presented in part at 5th International Congress on Pharmacology, July 23–28, 1972, San Francisco, California.     

Pharmacokinetics,Bioavailability, and Safety of Montelukast Sodium (MK-0476) in Healthy Males and Females

Purpose. The safety, tolerability, and pharmacokinetics of intravenous (i.v.) montelukast sodium (Singulair, MK-0476), and the oral bioavailability of montelukast sodium in healthy males and healthy females were studied. Methods. This was a two-part study. Part I was a four-period study in males of rising i.v. doses of montelukast sodium (3, 9, and 18 mg) administered as 15-minute constant-rate i.v. infusions (Periods 1–3), followed by a 10-mg oral tablet dose of montelukast sodium (Period 4) under fasting conditions. Part II was a four-period study in females of i.v. montelukast sodium (9 mg) infused over 15 and 5 minutes (Periods 5 and 6, respectively) or injected as a bolus over 2 minutes (Period 7), followed by a 10-mg oral tablet dose of montelukast sodium (Period 8). Plasma samples were collected and analyzed by HPLC. Results. In males (N = 6), as the i.v. dose of montelukast sodium increased from 3 to 18 mg, the area under the plasma concentration-time curve of montelukast sodium from time 0 to infinity (AUC) increased proportionately. The mean values of plasma clearance (CL), steady-state volume of distribution (V_ss), plasma terminal half-life (t_1/12), and mean residence time in the body (MRT^i.v.) of montelukast sodium were 45.5 ml/min, 10.5 1, 5.1 hr, and 3.9 hr, respectively, and remained essentially constant over the i.v. dosage range. Following oral administration of a 10-mg tablet of montelukast sodium, the AUC, maximum plasma concentration (C_max), time when C_max occurred (T_max), apparent t_1/12, mean absorption time (MAT), and bioavailability (F) of montelukast sodium averaged 2441 ng · hr/ml, 385 ng/ml, 3.7 hr, 4.9 hr, 3.4 hr, and 66%, respectively. Following i.v. administration of 9 mg of montelukast sodium to females (N = 6), the values of CL, V_ss, t_1/2, and MRT i.v. averaged 47.6 ml/min, 9.6 1, 4.5 hr, and 3.6 hr, respectively. Following oral administration of a 10-mg tablet to females, the mean AUC, C_max, T_max, apparent t_1/2, MAT and F were 2270 ng·hr/ml, 350 ng/ml, 3.3 hr, 4.4 hr, 2.6 hr, and 58%, respectively. These parameter values were similar to or slightly smaller than those in healthy males receiving the same i.v. and oral doses. Conclusions. The disposition kinetics of montelukast sodium were linear. Gender had little or no effect on the kinetics of montelukast sodium. Safety results from this study indicate that intravenous doses of montelukast sodium from 3 to 18 mg and a 10-mg oral dose are well tolerated.     

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

The present experiments dealt the effects of 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.     

Evaluation of P2-purinoceptor antagonists at two relaxation-mediating P2-purinoceptors in guinea-pig taenia coli

The guinea-pig taenia coli possesses two relaxation-mediating receptors for nucleotides: a prototypic P_2Y-purinoceptor, which is activated by adenosine 5-O-(2-thiodiphosphate) (ADPßS), and a separate receptor for ,-methylene ATP (,-MeATP). Effects of several as yet incompletely characterized P₂-purinoceptor antagonists at these receptors were examined.The concentration-relaxation curve of ADPßS was shifted to the right by reactive blue 2, suramin, 8-(3,5-dinitro-phenylenecarbonylimino)-1,3,5-naphthalenetrisulphonic acid (XAMR0721; at 1000 M only), pyridoxalphosphate-6-azophenyl-2,5-disulphonic acid (iso-PPADS), pyridoxal 5-phosphate, trypan blue and Evans blue (at 320 M only). Schild plots for the antagonism of reactive blue 2, suramin, iso-PPADS and pyridoxal 5-phosphate against ADPßS had slopes <1. The concentration-relaxation curve of ,-MeATP was shifted to the right by reactive blue 2, suramin, XAMR0721, iso-PPADS, pyridoxal 5-phosphate and trypan blue but not by Evans blue (320 M). Schild plots for the antagonism of suramin, XAMR0721 and iso-PPADS against ,-MeATP had slopes >1. Only XAMR0721 differed clearly in potency against the two nucleotides: it was considerably more potent against ,-MeATP than against ADPßS. 2-Methylthio ATP (MeSATP; 1 M) and ATP (100 M) were degraded by pieces of taenia coli. All antagonists except trypan blue attenuated the degradation of either or one of the two nucleotides.The selective effect of XAMR0721 against ,-MeATP confirms the existence of two relaxation-mediating P₂-purinoceptors in guinea-pig taenia coli. Comparison of the apparent affinities of the antagonists for the two taenia coli receptors with affinities for the P_2X-purinoceptor of the rat vas deferens shows that reactive blue 2, suramin, iso-PPADS, pyridoxal 5-phosphate and trypan blue have little selectivity for any of the three receptors. XAMR0721, which has been shown to possess relatively high affinity for the P_2Y-purinoceptor in turkey erythrocytes, was very weak at the P_2Y-receptor of the taenia, thus supporting the existence of pharmacologic P_2Y-receptor subtypes. Evans blue, with little effect in the taenia coli but a marked effect in the rat vas deferens, is the most selective P_2X-(versus P_2Y-) purinoceptor antagonist presently known, although its effect on the degradation of nucleotides must be kept in mind.     

Opposite modulation of ouabain cardiotoxicity by hexamethyleneamiloride and phenylephrine

Summary To see whether the Na/H antiporter plays a role in digitalis cardiotoxicity, we investigated the influence of modulators of Na/H exchange on the toxic effects of ouabain in isolated, paced (0.4 Hz) rat left atria. Ouabain (1 mmol/l) caused a transient positive inotropic effect followed by toxic events, including a complete loss of developed force and a gradual increase in resting force. In the presence of hexamethyleneamiloride (3 and 10 mo1/l), an inhibitor of Na/H exchange, ouabain (1 mmol/l) caused a sustained positive inotropic effect without toxicity. By contrast, phenylephrine (100 mol/ 1) an -adrenoceptor agonist reported to stimulate the antiporter, hastened the development of ouabain's toxicity. Neither ouabain, at a subtoxic concentration (650 ol/l), nor phenylephrine (100 mol/l) affected diastolic force, but in their combined presence, a substantial contracture developed and twitch contractions disappeared. Phenylephrine (30 or 100 mol/l) or adrenaline (30 mol/l), in the presence of a -adrenoceptor antagonist, increased the intracellular pH by up to 0.15 pH unit, as measured using ion-selective microelectrodes in quiescent preparations. This effect on pH₁ was prevented by hexamethyleneamiloride (10 mol/l). Consistent with phenylephrine's ability to stimulate Na⁺ influx via the Na/H antiporter, phenylephrine (100 mol/l) increased intracellular Na⁺ activity by about 3 mmol/l in ouabain (650 mol/l)-treated atria. These findings indicate that modulators of Na/H exchange affect the cardiotoxicity of digitalis glycosides and imply that the stimulation of myocardial -adrenoceptors may aggravate digitalis toxicity.This work was conducted in part under the auspices of the Association for US/French Biomedical Cooperation Send offprint requests to S. M. Vogel at the above address     

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

The effects of ⁹ (THC) on body temperature, catecholamine synthesis and plasma corticosteroid levels were examined in the mouse at ambient temperatures of 31°, 20° and 10°C in order to study the role of hypothermia in THC's other actions. THC produced hypothermia at 10° and 20°C, but not at 31°C. Dose related increases in dopamine and norepinephrine synthesis rates and plasma corticosterone levels were produced by THC at bot 31° and 20°C. The effects of THC at 10°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.     

Biological activities of some 5-substituted N,N-dimethyltryptamines, α-methyltryptamines,and gramines

Summary Three series of derivatives of N,N-dimethyltryptamine, -methyltryptamine and gramine bearing substituents of varying electronic nature on the C-5 position were tested for acute toxicity, effect on barbiturate sleeping time, antireserpine effect, swim maze, variable interval conditioned behavior, and inhibition of monoamine oxidase. No correlation could be made between the electronic effects and their pharmacological activities. It was thus suggested that there exist different pharmacological receptors for the tryptamines and gramines.This study was supported by grant MH-11168 from the U.S. Public Health Service, Bethesda, Md., and by the Britton Fund.     

Serum dopamine-Β-hydroxylase (DΒH) activity and affective states

Using a sensitive assay system recently developed, dopamine--hydroxylase (DH) was examined in the serum of 56 psychiatric patients and 33 normal control subjects. Blood values of this enzyme failed to differentiate between the various diagnostic populations explored and were compatible with values obtained for normal control subjects within the same age range. The findings are critically evaluated and their possible relevance discussed with regard to the role of catecholamines in affective disorders.This work was supported by USPHS Grants Nos. 17436 and MH 02717.     

Further studies of the aggressive behavior induced by Δ 9-Tetrahydrocannabinol in REM sleep-deprived rats

The aggressive behavior induced by ⁹-tetrahydrocannabinol in pairs of REM sleep-deprived rats was studied in five experiments by measuring dominant and submissive behavioral patterns. When 2 REM-deprived rats received ⁹-THC, one of the animals displayed very aggressive postures, while its partner assumed incomplete defensive postures. The intensity of these behavioral postures was dosedependent. In pairs composed of one REM-deprived rat injected with ⁹-THC and one normal or one REM-deprived partner injected with control solution the deprived/drugged rat showed an aggressive posture and catatonia, or a strikingly bizarre behavior, while the control partner displayed typical defensive postures. The behavioral alterations induced in REM-deprived rats by amphetamine, LSD-25, and pentobarbital failed to provoke defensive postures in the normal rats paired with them; however, apomorphine partially mimicked the ⁹-THC effects.It is concluded that in REM-deprived rats ⁹-THC not only provokes aggressive behavior but also impairs the defensive-submissive behavioral patterns.     

Effects of psychotropic drugs on Δ 9 long-lasting muricide

The effects of psychotropic drugs on THC-induced long-lasting muricide were investigated in rats. Changes in open field activity (ambulation and rearing) of the rat werre concurrently assessed as an index of behavioral toxicity. Imipramine-like antidepressants, atropine, and antiparkinsonism drugs exhibited a selective inhibitory activity on muricide, whereas the effects of neuroleptics, pentobarbital, diazepam, and methamphetamine were nonspecific. It is also suggested that cholinergic, catecholaminergic, and serotonergic mechanisms are involved in THC-induced muricide. This type of induced muricide appears to be a useful experimental model particularly suitable for the evaluation of antidepressants in correlation with brain amine dynamics.     

A role of red cell pyrimidine 5′-nucleotidase in experimental lead poisoning

Intravenous administration of lead acetate to rabbits for 10 weeks at 2 week intervals resulted in significantly elevated blood lead levels, slight anemia with marked microspherocytosis and moderate basophilic stippling, and marked depression of red cell-aminolevulinic acid (ALA) dehydratase activity. However the decrease in red cell pyrimidine 5-nucleotidase (P5N) activity was slight when compared to the red cell P5N activity of comparable reticulocyte-rich blood, and intracellular accumulation of pyrimidine nucleotides could not be demonstrated. In the in vitro inhibition test the same degree of inhibition of red cell P5N activity seen in hereditary red cell P5N deficiency was obtained by using a lead concentration 200–400 times higher than the lead levels detected in human plumbism. Most importantly, there were no differences in the lead-induced inhibition of human and rabbit red cell P5N.From the results of the in vitro inhibition test, lead-induced red cell P5N deficiency appears to be one of several pathogenic mechanisms in chronic lead exposure associated with the accumulation of lead in bone marrow. A decrease in red cell P5N activity could not be demonstrated despite the marked depression in red cell ALA dehydratase activity, and slight anemia with marked microspherocytosis and moderate basophilic stippling in this experiment. These results suggest that lead affects red cells at multiple metabolic loci.     

Δ9-Tetrahydrocannabinol produces naloxone-blockable enhancement of presynaptic basal dopamine efflux in nucleus accumbens of conscious,freely-moving rats as measured by intracerebral microdialysis

This study examined the effects of acute administration of delta-9-tetrahydrocannabinol (⁹-THC), the psychoactive ingredient in marijuana, on extracellular efflux of dopamine (DA) and its metabolites as measured by in vivo microdialysis in nucleus accumbens of conscious, freely-moving rats. ⁹-THC, at low doses (0.5–1.0 mg/kg), which significantly enhance brain stimulation reward (intracranial self-stimulation), significantly increased DA efflux in nucleus accumbens. Augmentation of DA efflux by ⁹-THC was abolished by removal of calcium (Ca⁺⁺) ions from the perfusion fluid, indicating a Ca⁺⁺-dependence of ⁹-THC's action. Augmentation of DA efflux by ⁹-THC was either totally blocked or significantly attenuated by doses of naloxone as low as 0.1 mg/kg. Given the postulated role of mesocorticolimbic DA circuits in mediating and/or modulating brain stimulation reward, the present data raise the possibility that marijuana's rewarding effects, and hence its euphorigenic effects and abuse potential, may be related to pharmacological augmentation of presynaptic DA mechanisms. Additionally, the DA mechanisms enhanced by marijuana appear to be modulated by an endogenous opioid peptide system.     

Acute effects of two tetrahydrocannabinols (Δ9-THC and Δ8-THC) on water intake in water deprived rats: Implications for behavioral studies on marijuana compounds

Water intake was studied in water deprived albino rats at various time intervals after injections of two tetrahydrocannabinols ( ⁹-THC and ⁸-THC) and solvents. The dose levels used were: 1.25, 2.5, and 5.0 mg/kg of ⁹-THC and 2.5, 5.0, and 10.0 mg/kg of ⁸-THC. The results show a clear, dose dependent inhibitory effect on water intake as compared to the controls.Reduced intake of food was seen at 1 day post injection. This effect was, however, significant only for the groups treated with 5.0 and 10.0 mg/kg of ⁸-THC. A decreased body weight was also recorded after the drug treatment, especially with ⁸-THC. With respect to cannabis-induced vocalization the data suggest an increased possibility of its appearance with increasing dosages of THC.     

Comparison of behavioral effects of synthetic (−)δ9-trans-tetrahydrocannabinol and marihuana extract distillate in chimpanzees

Eight chimpanzees emitted panel push responses under a procedure in which three operant schedules of positive reinforcement, each associated with a different stimulus, were presented successively. The fixed ratio (FR) schedule required the emission of 40 responses for reinforcement. Reinforcement under the differential reinforcement of low rate (DRL) schedule was delivered only for a response that followed the immediately preceding response by 10 or more sec. No responses were reinforced under the extinction or time out from reinforcement (TO) schedule. The behavioral effects produced by a marihuana extract distillate containing a known amount of (–) ⁹-trans-tetrahydrocannabinol ( ⁹-THC) were compared with those produced by a totally synthesized ⁹-THC. On four separate drug days each chimpanzee was orally administered one of the two compounds 2.5 h prior to experimentation in amounts yielding 1.0 mg/kg ⁹-THC. Only the DRL schedule performance was significantly affected by either drug compound. Both the marihuana extract and the synthetic ⁹-THC produced a statistically significant decrease in the percentage of correct DRL responses. However, no statistically significant differences between the drug effects produced by the two ⁹-THC dose forms were obtained.The authors wish to thank Michael Grisham for his help in collecting the data and Dr. Monique Braude for her continued support and guidance. Research supported by National Institute of Mental Health Contract No. HSM-42-71-15. Synthetic ⁹-THC and Marihuana Extract Distillate obtained by approval of the FDA-NIMH Psychotomimetic Agents Advisory Committee. The animals involved in this study were maintained in accordance with Guide for Laboratory Animal Facilities and Care as published by the National Academy of Sciences-National Research Council.     

Soft Drugs. XX. Design,Synthesis, and Evaluation of Ultra-Short Acting Beta-Blockers

A new type of ultra-short acting -blocker which might prove advantageous in treating acute arrhythmias was designed, synthesized and investigated. Based on the soft drug inactive metabolite approach, the inactive phenylacetic acid metabolite of both metoprolol and atenolol was reactivated by esterification with sulfur-containing aliphatic alcohols. Since the sulfur-containing moieties are labile to the ubiquitous esterases, the new compounds should be inactivated by a one step enzymatic cleavage back to the inactive phenylacetic acid derivative. Pharmacological and pharmacokinetic profiles of the new compounds were evaluated in rats and rabbits. Isoproterenol-induced tachycardia was inhibited with short-term infusion of each compound. This tachycardia blocking effect rapidly disappeared upon termination of infusion, while -blocking activity was 2–4-fold longer after comparable doses of the short-acting -blocker, esmolol. The rapid recovery from the -receptor blockade is believed due to fast hydrolysis of the soft drugs in the body. This is supported from in vitro results showing the t_l/2 of esmolol is about 10-fold longer than the new soft drugs in rat, rabbit, dog and human blood. Hydrolysis studies in phosphate buffered solutions indicated that the esters are labile to base-catalyzed hydrolysis. However, the relative t_1/2 values measured in biological media compared to phosphate buffered solution clearly support rapid enzymatic cleavage of the soft drugs. Interestingly, one of the soft -blockers, the sulfonyl ester derivative, showed a unique property of exhibiting good -receptor blocking activity without significant hypotensive action.     

Inhibition by interleukin-1\ of noradrenaline release in rat spleen: involvement of lymphocytes,NO and opioid receptors

Effects of indomethacin, N-nitro-L-arginine (NNA) and naloxone, and of pretreatment with cyclophosphamide (CY), on the interleukin (IL)-I\ induced inhibition of exocytotic noradrenaline release were investigated in the isolated, vascularly perfused spleen of the rat. Neurotransmitter release was evoked by perivascular electrical stimulation (4 Hz) and the overflow of endogenous noradrenaline was determined by HPLC with electrochemical detection.Perfusion of the spleen with Tyrode's solution containing IL-1\ (100 pg/ml) for 90 min caused an inhibition of the stimulation-evoked noradrenaline overflow which persisted for at least 20 min after washout of the IL. The evoked overflow was reduced in the presence of NNA 30 mol/l, but remained unaffected by indomethacin 3 mol/l, naloxone 0.1 mol/l or treatment of the rats with CY (250 mg/kg). The opioid agonist etorphine 10 mol/1 inhibited the evoked overflow of noradrenaline and this effect was prevented by naloxone 0.1 mol/1. The inhibition of evoked overflow by IL-1\ was not affected by indomethacin but was reduced or even prevented in the presence of NNA or naloxone, or after lymphocyte depletion of spleens by CY.The results are compatible with the idea that in the rat spleen exocytotic noradrenaline release is accompanied by a concomitant secretion of a nitric oxide (NO)-like compound which, in turn, reinforces noradrenaline release, and that the release can be inhibited via prejunctional opioid receptors. The IL-1\ induced inhibition of evoked release appears to be a complex process which involves as one of many steps a decrease of the facilitatory NO-like compound and the release of endogenous opioids probably from spleen lymphocytes.