Effect of delta-THC on ethanol withdrawal in mice

Delta-THC (10 mg/kg, i.p.) administered to mice immediately after withdrawal from a 3-day exposure to ethanol vapor was found to intensify withdrawal reactions. No effect was seen when delta-THC was administered chronically during the exposure to ethanol.

Hydrolysis of carbon-labeled cocaine in human serum

Hydrolysis of 14C-cocaine in human serum, separation of the metabolites on TLC, and subsequent identification on GLC is described. AT 1 H, 20 percent of the cocaine was metabolized to benzoylecgonine, ecgonine and ecgonine methylester. At this time interval the highest percent of product was in the form of the ecogonine methyl ester, a metabolite not previously reported in humans. After 4 h, 67 percent of the cocaine was hydrolyzed; of this, 45 percent was benzoylecgonine and ecgonine in a ratio of 1.6 to 1. The half-life for cocaine hydrolyzed in human serum was approximately 2.5 h.

Demethylation in rats chronically treated with cocaine

Norcocaine was prepared from cocaine utilizing diethyl azodicarboxylate. The rate of demethylation of 14C-cocaine in rats receiving either chronic or acute dosages of the drug was investigated. No significant difference in the rate of 14CO2 exhalation from the two groups was observed.

Discriminative response control by psychomotor stimulants

Psychomotor stimulants are capable of controlling discriminative responding in rats. Evidence suggests that response control is central, of a fairly specific nature, and dependent on intact dopaminergic functions.

Role of dopamine in d-amphetamine-induced discriminative responding

In two-lever operant chambers, rats were trained in a food-reinforced discrimination task. Reward was contingent upon correct lever choices to the induced differential cue conditions of d-amphetamine (0.8 mg/kg) or saline throughout training on a differential reinforcement of low response rate (DRL-15 sec) schedule. Upon acquisition of discriminative response control the animals were pretreated with various neurochemical agents. Pretreatment with atropine, phentolamine, propranolol, methysergide or cinanserin did not block production of d-amphetamine lever responding. Nicotine and oxotremorine did not produce the amphetamine-like cueing effect. However, pimozide blocked the ability of animals to discriminate d-amphetamine and L-DOPA, in combination with Ro 4-4602 with or without amantadine, generated amphetamine-like responses. These results indicate a role of dopamine in the production of the amphetamine state and from the failure of apomorphine to exhibit the stimulus property of d-amphetamine and the antagonism by alpha-methyltyrosine of the d-amphetamine responding it is further suggested that this amphetamine state is produced via the releasing of newly synthesized dopamine.

Role of serotonin in the discriminative stimulus properties of mescaline

Rats were trained to discriminate intraperitoneally administered mescaline from saline in a two-lever operant chamber for food reinforcement. Reward was contingent upon responses made greater than 15 sec apart (DRL-15) on the appropriate lever paired with either drug or saline administration. Following the establishment of discriminative response control by mescaline, the animals were tested for stimulus generalization produced by mescaline after: (a) blockade of periphreral and central serotonin (5-HT) receptors with cinanserin, methysergide, or cyproheptadine; (b) blockade of peripheral 5-HT receptors with xylamidine tosylate; and (c) depletion of brain 5-HT with the tryptophan hydroxylase inhibitor p-chlorophenylalanine (PCPA). The results show that all three central 5-HT antagonists greatly reduced the discriminability of mescaline while the peripheral antagonist, xylamidine tosylate, was without effect. Furthermore, these agents at the doses employed did not effect the discriminability of saline. Depletion of 5-HT with PCPA potentiated the effects of a sub-threshold dose of mescaline and slightly reduced the discriminability of saline. The results indicate that mescaline produces its discriminative stimulus properties by directly stimulating central serotonergic receptors.

Effects of intraventricular injections of N-6,O-2-Dibutyryl adenosine 3,5-monophosphate on the rat brain cholinergic system

Intraventricular injections of dibutyryl cyclic AMP effected increases of acetylcholine in the cerebral cortex-striatal and subcortical regions. No increase in choline acetyltransferase activity was observed; however, there was a significant decrease in acetylcholinesterase activity in the subcortical region.

Some pharmacological actions of 2,5-dimethoxy-4-ethylamphetamine (DOET) in rats and mice

DOET, like DOM, exhibited pressor action in rats. This increase of blood pressure was blocked by pretreatment with cinanserin. DOET at high doses decreased the spontaneous locomotor activity of mice at the first hour but increased the activity at the second hour; a low dose was less effective. DOET also increased the rectal temperature of rats and this hyperthermic action was suppressed by pretreating the animals with cinanserin or methysergide. These actions of DOET were compared with those of DOM.

Discriminative stimulus properties of mescaline: mescaline or metabolite?

The purpose of this study was to investigate possible similarities in the interoceptive stimuli produced by mescaline and its metabolites. Rats were trained in a 2 lever operant chamber to discriminate between the drugged state (mescaline 25 mg/kg) and the nondrugged state (saline). Following acquisition of discriminative response control the rats were pretreated with either saline, aldehyde dehydrogenase inhibitors or amine oxidase inhibitors and tested stimulus generalization produced by i.p. injections of 3, 4, 5-trimethoxyphenylethanol (TMPE), 3, 4, 5-trimethoxyphenylacetaldehyde (TMPA), N-acetylmescaline, mescaline or saline. The results indicated that both aldehyde dehydrogenase and amine oxidase inhibitors enhanced the effects of mescaline, while TMPE, TMPA and N-acetylmescaline failed to exhibit generalization to the mescaline state, regardless of pretreatment. These findings do not indicate the role of a metabolite in the interoceptive cue produced by mescaline.

Differentiation of pressor and behavioral effects of d-amphetamine and 2,5-dimethoxy-4-methylamphetamine (STP) by cinanserin

Cinanserin was used to differentiate the effects of d-amphetamine and 2,5-dimethoxy-4-methyl-amphetamine (STP) on blood pressure and spontaneous locomotor activity in rats and mice. Cinanserin itself produced a decrease of blood pressure and spontaneous locomotor activity in the animals. A dose of 2 mg/kg of cinanserin blocked the increase of blood pressure caused by STP; however, it failed to affect the pressor action of d-amphetamine even when the dose was increased to 25 mg/kg. The increase of spontaneous locomotor activity induced by d-amphetamine was counteracted by cinanserin (10 mg/kg) but cinanserin (10 and 25 mg/kg) did not modify spontaneous locomotor activity produced by STP. The results showed that the pressor actions of STP and d-amphetamine, and most likely also their effects on spontaneous locomotor activity, were involved in different mechanisms.