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Biomedical subjects

S J Mulé

Publications and source records attributed to S J Mulé.

11 recordsLinked to original sources

Comparative effects of cocaine and pseudococaine on EEG activities, cardiorespiratory functions, and self-administration behavior in the rhesus monkey.

The effects of cocaine and pseudococaine on the EEGs, heart and respiratory rates, and self-administration behavior were studied in rhesus monkeys. An intravenous injection of cocaine (2.5 and 4.0 mg/kg) in the monkey produced low-voltage fast waves (LVFWs) in the EEGs and behavioral hyperexcitation accompanied by marked increases in the heart and respiratory rates with mydriasis and excessive salivation. In contrast, pseudococaine produced high-voltage slow waves (HVSWs) in the EEGs and behavioral depression accompanied by the same symptoms of the autonomic functions as those produced by cocaine. Both isomers were self-administered by the monkeys. During cocaine self-administration sessions, the animals showed hyperexcitation in their overall behavior, while with pseudococaine they showed almost normal behavioral responses. These results suggest that cocaine produced excitatory effects and pseudococaine inhibitory effects on the EEGs and behavior. Both isomers stimulate the heart and respiratory rates, and were self-administered by the monkeys.

Animals

Evaluation of the radioimmunoassay for benzoylecgonine (a cocaine metabolite) in human urine.

The 125I-radioimmunoassay (RIA) for benzylecgonine (cocaine metabolite) in urine was evaluated by comparison with gas-liquid chromatography (GLC) and thin-layer chromatography (TLC) and the Enzyme-Multiplied Immunoassay Technique (EMIT). By RIA, a statistically significant concentration, 2 microng/liter, was observed for urinary benzoylecgonine. The coefficient of variation for the RIA was 2.58+/-0.38% inter-assay and 2.20+/-0.14% intraassay. There was cross-reactivity with cocaine (more reactive than benzoylecgonine) and other members of the tropane family of alkaloids. There was agreement between results by RIA and GLC in 95.5% of the samples, between RIA and TLC in 87.0%, and between RIA and EMIT in 84.5%. The percentage of true false-positives was 3.5% for the RIA in comparison to GLC, 8.8% in comparison to TLC, and 9.1% in comparison to EMIT. True false-negatives were insignificant (0 to 1.0%). GLC and RIA results correlated highly (phi=0.908). GLC, therefore, was the best comparison method for this evaluation study. RIA for benzoylecgonine is sensitive, reproducible, and reliable for the detection of cocaine in urine.

Chromatography, Gas

The specificity of binding of the narcotic agonist etorphine in synaptic membranes of rat brain in vivo.

When 3H-etorphine was administered to rats in a pharmacologically effective dose (0.75 mug/kg intracisternally), the labeled drug was concentrated in synaptic membrane fractions isolated from the brains of rats killed 10 min after etorphine injection. Pretreatment of the animals with the narcotic antagonists naloxone, diprenorphine or l-cyclorphan, blocked the pharmacological responses to etorphine and reduced 3H-etorphine binding in the membrane fractions. The differences between 3H-etorphine bound in synaptic membranes of rats treated with d-cyclorphan (inactive isomer) and l-cyclorphan (active antagonist) were in the same range as the reductions in etorphine binding in antagonist-treated rats, indicating that stereospecific and pharmacologically-specific binding sites in synaptic membranes in vivo were of the same magnitude: about 0.04 pmol/g brain.

Animals

A gas-liquid chromatographic method for the determination of naltrexone and beta-naltrexol in human urine.

A rapid quantitative method was developed to assay in urine naltrexone and its major urinary metabolite, beta-naltrexol. Following solvent extraction and elimination of interfering materials, the weakly basic drug, its metabolite and the internal standard (etorphine) were silylated and analyzed by gas-liquid chromatography. As little as 0.02 mug/ml of naltrexone and beta-naltrexol was detectable using a hydrogen flame ionization detector. Twenty-four-hour urine samples were analyzed from three subjects taking 180 mg naltrexone daily. The major urinary excretion product was beta-naltrexol which accounted for 48.6% of the administered dose. Only 5% of the administered dose excreted in the urine was naltrexone. Beta-naltrexol was excreted 70% as free drug and 30% conjugated while naltrexone was 90% conjugated.

Chromatography, Gas

Disposition of (15,16-3H)naltrexone in the central nervous system of the rat.

After injection of (15,16-3H)naltrexone (10 mg/kg s.c.) in male Wistar rats, peak concentrations of drug occurred in brain and plasma within 0.5 hr. Levels of naltrexone were sustained in brain between 2 and 24 hr and were barely detectable at 48 hr. Significant amounts of metabolities were present in brain and plasma at longer time periods. The t1/2 of naltrexone in brain and plasma were approximately 8.0 and 11.4 hr. respectively. The brain/plasma ratios of naltrexone at earlier times (0.5-1 hr) were higher than those at later times. The binding of naltrexone in vitro with rat plasma proteins in concentrations of 1-10 mug/ml ranged between 41 and 59% 6beta-Naltrexol was present in very small amounts in brain but not in plasma. In addition to 7,8-dihydro-14-hydroxynormophinone and 7,8-dihydro-14-hydroxynormophine, tentative evidence was obtained for three other metabolites of naltrexone in brain. These metabolites were also present in plasma in addition to free and conjugated naltrexone and its N-dealkylated metabolites.

Animals