Biomedical subjects
Publications and source records attributed to M D Aceto.
(-)-9-Nor-9beta-hydroxy-hexahydrocannabinol[(-)-9-nor-9beta-OH-HHC] produced hypotension and bradycardia in anesthetized dogs, was a potent antinociceptive agent in the mouse tail-flick and p-phenylquinone abdominal-stretching tests, but did not reverse the effects of morphine withdrawal in dependent monkeys.
Mice were given a drug per os and 2 h later were challenged with an intravenous LD95 of nicotine. Amitriptyline, imipramine, doxepin, meprobamate, chlordiazepoxide, diazepam, trifluoroperazine, haloperidol, thioridazine, chlorpromazine, phenobarbital, propranolol and diphenylhydantoin were all active in protecting mice from extensor convulsions and lethality. Iproniazid, tranylcypromine, atropine, benztropine and trimethadione were inactive. There appears to be a relationship between blockage of nicotine-induced extensor convulsions and lethality in mice and sedative-antianxiety effects in man. This relationship is especially good for drugs designated antidepressant, antianxiety and antipsychotic.
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1. Subcutaneous injections of opiates produced the Straub tail reaction in mice. The potencies of the opiates in mice were consistent with previous estimates of the analgesic potencies in animals and in man.2. The potencies of sixteen antagonists in counteracting the reaction were consistent with those previously obtained with the rat tail-flick test.3. The (-) isomers of four benzomorphan derivatives were much more potent in counteracting the reaction than their (+) isomers and about twice as potent as their racemates. The activity of the isomers seemed to follow Pfeiffer's rule: the lower the effective dose of a drug, the greater the difference in the pharmacological effects of the optical isomers. One of the trans isomers acted like an opiate, while its cis isomer acted like an antagonist.4. Naloxone and nalorphine fulfilled conventional criteria for competitive antagonism, whereas atropine and the (-) and the (+) isomers of pentazocine and of cyclazocine did not do so.5. The Straub tail test seems to be useful for studying structure-activity relations among opiates and opiate antagonists.
1. The ganglion blocking agents, chlorisondamine, pentamethonium, mecamylamine, decamethonium and hexamethonium all block nicotine extensor convulsions when administered intraventricularly in mice. Tetraethylammonium was inactive.2. For the intraventricular route, there is a relationship between ganglionic blocking potency and blocking of nicotine extensor convulsions. Indirect evidence suggests that the site(s) of action of nicotine extensor convulsions and lethality is central in origin and associated with brain areas near the ventricles.3. When ganglion blocking agents are given orally, subcutaneously or intravenously varying degrees of protection can be observed probably depending on factors such as whether or not the drugs cross the blood-brain barrier, absorption, etc., and the effectiveness in protecting mice from nicotine is not related to ganglionic blocking potency.4. Atropine and morphine given intraventricularly or subcutaneously did not protect mice from the LD95 of nicotine. Chlorpromazine gave very erratic results and phenobarbitone was effective subcutaneously and to a lesser extent intraventricularly.
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Despite the fact that high doses of cocaine are abused chronically, relatively little is known regarding the development of tolerance and/or sensitization under these circumstances. Therefore, male Sprague-Dawley rats were infused continuously i.v. for 10 days, at a rate of 150 mg/kg/day (0.1 mg/kg/min) with cocaine hydrochloride. Body weight, food and water consumption, urine and fecal excretion, as well as blood pressure, heart rate and stereotypic behavior were monitored daily. Blood samples were also drawn daily so that plasma could be analyzed for cocaine and BEG by gas chromatography/mass spectrometry. Severe body weight loss on days 1 through 4 was followed by a gradual return to pre-drug levels. In addition, cocaine's effects on food and water consumption and urine and fecal excretion, which were maximal by day 2, were imperceptible by day 5. Complete tolerance developed rapidly to the remarkable rise in blood pressure noted on the first day. However, tolerance did not develop to the cocaine-induced increase in heart rate. A profound decrease in heart rate was noted in some animals which was interpreted to be cardiotoxicity since these animals subsequently died. On the other hand, sensitization or intensification of behavioral stereotypy occurred during the first 2 days followed by complete tolerance to this effect by day 5. No withdrawal phenomena were noted 24 h after cocaine was abruptly withdrawn. Plasma concentrations of cocaine rose rapidly during the first day and remained elevated at a constant level until day 5. Then, a sharp decline in plasma levels occurred at day 6 which remained depressed for the duration of the infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
This study was designed to characterize the cocaine-induced rausch or hyperarousal syndrome in rhesus monkeys. This syndrome mimics the stage observed in human abusers bingeing on cocaine and is considered crucial in the progression from recreational use to compulsive abuse. However, little research has focused on this important aspect of cocaine use. Cocaine was administered i.v. at doses of 0.0, 0.5, 1.0 and 2.0 mg/kg. Plasma concentrations were determined by gas chromatograph mass spectrometry (GC/MS) using deuterated internal standards d3 cocaine and d3 benzoylecgonine (BE). Mean plasma concentrations of cocaine, were on samples collected 1 min after infusion, 46 +/- 31, 88 +/- 15 and 275 +/- 116 mg/microliters in the 0.5, 1.0 and 2.0 mg/kg dose groups, respectively. There were no detectable concentrations of BE in any of the specimens nor was cocaine detected in the saline controls. Analysis of the behavioural data revealed that the 0.5 and 1.0 mg/kg results were intermediate between the results obtained at doses of 0.0 and 2.0 mg/kg and that the 1.0 mg/kg dose produced a higher response than the 0.5 mg/kg dose up to the 12 min. Regarding individual behavioural signs, those designated escape attempts, checking, feinting, restlessness, searching, vocalizing, chewing, crouching and wide-eyed were noted most frequently. The results showed dose-response relationships for both plasma concentrations of cocaine and for the total number of overt behavioural signs. The plasma concentrations were in the range reported for human cocaine abusers.
A convenient GC/MS method for the quantitation of nicotine is described. Brief and rapid tolerance to the hypertensive action of nicotine was observed during acute administration. Rats continuously exposed to (+)- or (-)-nicotine for 6 days showed significant dose-related suppression of water intake and body-weight decreases for the initial 4 days; then water consumption slowly returned to control levels, while body weight increased, but failed to reach control levels. During the withdrawal period, water consumption rose to levels significantly higher than that of the tartaric acid and water controls. Body weight during the withdrawal phase continued to increase but remained below those of control animals. Blood concentration of nicotine during acute tolerance was found to be 64.3 +/- 17.8 ng/ml whereas the saline controls showed levels of 0.67 +/- 0.67 ng/ml. Nicotine levels which were not detectable before the administration of nicotine, were elevated and constant during days 1 and 6 of the infusion period (320 +/- 80 ng/ml of plasma) and fell to below levels of detectability 24 hr after the termination of the infusion.