Δ⁹-Tetrahydrocannabinol (THC) inhibited ulcer formation in the pylorus-ligated rat (Shay rat test). However, this antiulcer activity of THC was substantially less than for the anticholinergic substance tridihexethyl chloride both in terms of degree of activity and potency. In addition, the results of the present study suggested different mechanism(s) of action for the antiulcer effects of these substances.

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Tetrabenazine evoked a biphasic response in rectal temperature of the rat following intraperitoneal administration of 4.4–70.0 mg/kg. The initial hyperthermia was inversely related to the dose while the subsequent hypothermia was dose-dependent. This biphasic effect on temperature was similar to that seen with THC at 0.5 mg/kg, thus adding further evidence of a similarity in the mode of action of the two drugs. In contrast, only hypothermia was evident following chlorpromazine administration.

SummaryMeseclazone and its major metabolite, 5-chlorosalicylic acid (5-CSA) have been shown to possess anti-inflammatory, analgesic and antipyretic activity. The comparative effects of these compounds on platelet aggregation were evaluated in vitro and ex vitro with acetylsalicylic acid (ASA). in vitro, meseclazone and ASA exhibited almost identical inhibitory potency of secondary phase ADP aggregation while 5-CSA was less effective. Moreover, collagen aggregation was inhibited by all three agents: ASA > meseclazone > 5- CSA. Thrombin-induced aggregation was inhibited to approximately the same extent by 5- CSA and ASA while meseclazone was inactive. The in vitro effects on the release-inducing aggregants were confirmed by ex vitro experiments in rats. These demonstrated that ASA and meseclazone inhibited collagen-induced aggregation 1 and 4 hr after oral administration although ASA was three to four times more active. ASA, but not meseclazone, was still effective 24 hr after administration. Bleeding times in rats 1 and 4 hr following oral administration of meseclazone and ASA were not altered. It is concluded that meseclazone and/or 5-CSA inhibit in vitro and ex vitro platelet aggregation initiated by the release reaction similar to ASA and other non-steroidal anti-inflammatory drugs.