The hallucinogenic herb Salvia divinorum and its active ingredient salvinorin A inhibit enteric cholinergic transmission in the guinea-pig ileum.

Salvia divinorum is a widespread hallucinogenic herb traditionally employed for divination, as well as a medicament for several disorders including disturbances of gastrointestinal motility. In the present study we evaluated the effect of a standardized extract from the leaves of S. divinorum (SDE) on enteric cholinergic transmission in the guinea-pig ileum. SDE reduced electrically evoked contractions without modifying the contractions elicited by exogenous acetylcholine, thus suggesting a prejunctional site of action. The inhibitory effect of SDE on twitch response was abolished by the opioid receptor antagonist naloxone and by the kappa-opioid antagonist nor-binaltorphimine, but not by naltrindole (a delta-opioid receptor antagonist), CTOP (a mu-opioid receptor antagonist), thioperamide (a H(3) receptor antagonist), yohimbine (an alpha(2)-receptor antagonist), methysergide (a 5-hydroxytryptamine receptor antagonist), N(G)-nitro-L-arginine methyl ester (an inhibitor of NO synthase) or apamin (a blocker of Ca(2+)-activated K(+) channels). Salvinorin A, the main active ingredient of S. divinorum, inhibited in a nor-binaltorphimine- and naloxone-sensitive manner electrically induced contractions. It is concluded that SDE depressed enteric cholinergic transmission likely through activation of kappa-opioid receptors and this may provide the pharmacological basis underlying its traditional antidiarrhoeal use. Salvinorin A might be the chemical ingredient responsible for this activity.

Lack of evidence for significant hepatitis B transmission in Australian Rules footballers.

OBJECTIVE: To determine the prevalence of markers of past hepatitis B infection among participants in Australian Rules football, to estimate the potential exposure of Australians to hepatitis B virus (HBV) in contact sport. DESIGN AND SETTING: A point prevalence survey for antibody to hepatitis B surface antigen (anti-HBs) and core antigen (anti-HBc), supported by a questionnaire used to determine the history of risk and exposure, in South Australian National Football League (SANFL) players supervised at club level by general practitioners and sports medicine specialists. PARTICIPANTS: Of 245 players from seven clubs, 49 were excluded from the study because they had been previously vaccinated. Of 196 eligible participants, 117 submitted blood samples and, of these, 85 returned questionnaires. RESULTS: One player was positive for anti-HBc (a prevalence rate of 0.85%). This individual and three anti-HBc-negative players were positive for anti-HBs in the absence of a history of vaccination. We could not ascertain whether these additional three players had been previously infected, or vaccinated without this fact having been recorded on the questionnaires. No single behavioural factor correlated with positive anti-HBs results. CONCLUSIONS: The prevalence of markers of past hepatitis B infection in SANFL football players was no different to that in blood donors of the same age group from the same city. There was no evidence for any additional HBV transmission due to participation in football over that in the blood donor population. Vaccination of footballers and people engaged in similar sports is of benefit in conferring protection on the individual, but would be unlikely to make a significant public health impact on community rates of HBV infection.

Salvia divinorum and salvinorin A: new pharmacologic findings.

The diterpene salvinorin A from Salvia divinorum (Epling and Jativa-M), in doses of 200-500 micrograms produces effects which are subjectively identical to those experienced when the whole herb is ingested. Salvinorin A is effectively deactivated by the gastrointestinal system, so alternative routes of absorption must be used to maintain its activity. Traditionally the herb is consumed either by chewing the fresh leaves or by drinking the juices of freshly crushed leaves. The effects of the herb when consumed this way depend on absorption of salvinorin A through the oral mucosa before the herb is swallowed.

Aspirin kinetics and platelet aggregation in man.

Our aims were (1) to determine the effect of six commercially available aspirin (ASA) preparations on in vitro platelet aggregation, and (2) to relate changes in platelet function to ASA kinetics. Each of six subjects took a single dose of one of the following preparations--600 mg Asproclear, 600 mg Bufferin, 600 mg Bi-prin, 600 mg compressed ASA, 650 mg Ecotrin, or 650 mg S.R.A.--in random order every 3 wk. Venous blood was drawn before and at 2, 4, 6, and 24 hr after ASA dosage to measure platelet aggregation in response to collagen and adenosine diphosphate and, at more frequent intervals, to characterize ASA kinetics. Asproclear, Bufferin, Bi-prin, and compressed ASA yielded peak plasma ASA levels of 28 to 56 mumol/l (5 to 10 mg/l) within 15 to 60 min and peak salicylic acid (SA) levels of 72 to 290 mumol/l (10 to 40 mg/l) within 2 hr. Ecotrin and S.R.A. yielded plasma SA levels of 14 to 87 mumol/l (2-12 mg/l) within 4 to 24 hr and no measurable ASA at any time after dosing. Platelet aggregation was inhibited to an equal extent by all preparations. The time course for this inhibition was the same for all preparations but Ecotrin (which led to a more delayed effect). There was significant recovery of collagen-induced platelet aggregation at 24 hr with all preparations but Ecotrin. With Ecotrin and S.R.A. there was inhibition of platelet aggregation in the absence of measurable circulating ASA. We postulate that this was due to acetylation of cyclooxygenase in the portal circulation and that inhibition of peripheral cyclooxygenase may be spared.