5HT3 receptor antagonists do not block nicotine induced hyperactivity in rats

The effects of 5-HT3 receptor antagonists (ondansetron 0.1 mg kg-1 SC 30 min; bemesetron 0.03 mg kg-1 SC 45 min) on nicotine-induced increases in locomotor activity were measured in male Sprague-Dawley rats. Intermittent daily injections of nicotine (0.3-1.2 mg kg-1 SC 30 min) resulted in increased locomotor activity as measured by photocell counts. The effect of nicotine was not affected by administration of the 5-HT3 receptor antagonists at doses that are reported to block nicotine- and morphine-induced place-preference conditioning. Neither of the 5-HT3 receptor antagonists tested affected activity counts in vehicle treated animals. Nicotine-induced hyperactivity was blocked by the dopamine antagonist haloperidol (0.03 mg kg-1 SC 2 h) and by the nicotinic antagonist mecamylamine (1 mg kg-1 SC 1 min). The effects of a range of doses (0-1 mg kg-1) of the 5-HT3 receptor antagonists ondansetron, bemesetron, granisetron and tropisetron on hyperactivity induced by 0.6 mg kg-1 nicotine were then assessed. Only tropisetron at 1 mg kg-1 attenuated nicotine-induced hyperactivity. To demonstrate the efficacy of the present range of doses of the 5-HT3 receptor antagonists in this study, conditioned taste aversion experiments were conducted. Ondansetron (0.1 mg kg-1) failed to attenuate a conditioned taste aversion to saccharin induced by nicotine (0.6 mg kg-1), but did induce a reduction in saccharin preference in choice tests following three saccharin-ondansetron pairings.(ABSTRACT TRUNCATED AT 250 WORDS)

Behavioural response to SKF 38393 and quinpirole following chronic antidepressant treatment

The effects of chronic administration of antidepressant drugs (21-22 days s.c. via osmotic mini-pumps) on the behavioural responses of male Sprague-Dawley rats to (-)-quinpirole hydrochloride (0.05 mg kg-1 s.c., 5 min) and (+/-)-SKF 38393 hydrochloride (10 mg kg-1 s.c., 5 min) were investigated. Desipramine hydrochloride (10 mg kg-1 per day), phenelzine sulphate (10 mg kg-1 per day) and clorgyline hydrochloride (1 mg kg-1 per day) attenuated the suppression of locomotor activity induced by quinpirole, a dopamine D2-like receptor agonist, while clomipramine hydrochloride (10 mg kg-1 per day) was without effect. Yawning elicited by quinpirole was absent in phenelzine- and clorgyline-treated rats, but unaffected in rats treated chronically with desipramine and clomipramine. SKF 38393, a dopamine D1-like receptor agonist, significantly increased locomotor activity and time spent grooming in control animals. There were no significant effects of antidepressants on the behavioural responses to SKF 38393.

Toward comprehensive school drug policy in Ontario

The study reported here examines the development and implementation of School Drug Policy in Ontario Boards of Education, the components of these policies, and the composition of policy development committees. Data from 125 Boards of Education were obtained from responses to a questionnaire administered in the Fall of 1991. Findings from the study indicate that school drug policies are increasingly comprehensive-including not only disciplinary measures, but also a preventive curriculum and early intervention component. The composition of policy development working groups normally consisted of such groups as board personnel, teachers, and practitioners from other fields. Students were not often included in the process of policy development. Thus, the development and implementation of school drug policy in Ontario indicates a "top down" rather than "bottom up" approach.

Chronic antidepressant drug treatment attenuates motor-suppressant effects of apomorphine without changing [3H]GBR 12935 binding

The effects of chronic administration (28 days s.c. via osmotic minipumps) of the antidepressants phenelzine sulphate, desipramine hydrochloride and clomipramine hydrochloride (each at 10 mg/kg per day) on dopamine function have been measured in rats. Both phenelzine and desipramine attenuated the suppression of locomotor activity induced by apomorphine hydrochloride (0.05 mg/kg s.c. 15 min). Clomipramine did not affect the behavioural response to apomorphine. Analyses of brain tissue from these animals using the radioligand [3H]GBR 12935 revealed that there were no changes in dopamine uptake site density or affinity following the administration of phenelzine, desipramine or clomipramine. Analyses of brain monoamine oxidase activity and tricyclic levels were used to confirm the efficacy of the drug administration protocol. These data indicate that changes in dopamine uptake site density do not mediate antidepressant-induced changes in behavioural responses to apomorphine.

Purification and partial amino acid sequence of a bovine cartilage-derived collagenase inhibitor

An inhibitor of mammalian collagenase from bovine scapular cartilage has been purified to homogeneity. The inhibitor, extracted from cartilage using 2 M NaCl, was applied to an A-1.5m gel filtration column. Inhibitor eluted at an apparent Mr of 28,000. Further purification was achieved by ion exchange chromatography, gel filtration, and reverse-phase high performance liquid chromatography. A purification of greater than 1,000-fold was achieved. The inhibitor was judged homogeneous by the appearance of a single band on a silver-stained 15% sodium dodecyl sulfate-polyacrylamide gel. Reduced inhibitor had an Mr of 27,400, unreduced inhibitor had an Mr of 23,900. NH2-terminal sequence data were obtained for the first 45 residues. The bovine cartilage-derived inhibitor exhibits greater than 65% homology over the first 23 residues with a collagenase inhibitor purified from human skin fibroblasts maintained in cell culture. This is the first demonstration that collagenase inhibitors extracted directly from tissue may be similar to those obtained from culture medium.