Reduced P50 auditory gating response in psychiatrically normal chronic marihuana users: a pilot study.

BACKGROUND: Neurophysiological studies of marihuana (THC) often contain uncontrolled confounds [psychiatric diagnoses, polydrug use, central nervous system (CNS)-relevant injury, etc.] that can alter electrophysiological measures. This P50 sensory gating report is part of a larger neurophysiological and neurocognitive investigation of chronic THC exposure using rigorously screened medically and psychiatrically normal individuals without concurrent use of non-THC substances. METHODS: Following medical and psychiatric screening, including serial urine drug screens, technically adequate P50 paired auditory recovery tests were obtained on 19 chronic THC users and 14 control subjects. Fifty pairs of 80-dB auditory clicks (1 pair per 10 sec, 500-msec interclick separation) were delivered through earphones. The sensory gating measure was the ratio between the P50 amplitudes at the vertex elicited by the conditioning (first) and test (second) click. RESULTS: THC subjects had significantly higher sensory gating ratios (i.e., reduced suppression) than did control subjects. Among THC users, sensory gating ratios did not correlate with duration or frequency of THC use, although subjects with ratios above 40 had nearly twice the number of "joint-years" of THC exposure than did those with lower ratios. CONCLUSIONS: Reduced P50 suppression in the sensory gating paradigm may be a possible neurophysiological CNS sequela of long-term cumulative exposure to THC.

Comparison of efficacy of ginger with various antimotion sickness drugs.

UNLABELLED: Ginger and several other medications were compared with scopolamine and d-amphetamine for effectiveness in prevention of motion sickness. METHODS: Double-blind techniques were used. The subjects were given the medications two hours before they were rotated in a chair making head movements until a symptom total short of vomiting was reached. Standardized N.A.S.A. techniques were used for speed of rotation and end-point of motion sickness. RESULTS: The three doses of ginger were all at the placebo level of efficacy. Amitriptyline, ethopropazine and trihexyphenidyl increased the tolerated head movements but the increase was not statistically significant. Significant levels of protection were produced by dimenhydrinate, promethazine, scopolamine and d-amphetamine. Protection was further increased by combination of these latter drugs with d-amphetamine. Efficacy was greatest as the dose was increased. CONCLUSIONS: The medication of choice in this study was scopolamine 0.6 mg with d-amphetamine 10 mg. This combination provided good protection with acceptable side effects.

Toxicology of ipecac: a review.

The general effectiveness and safety of Ipecac syrup, per se, has not been questioned, but rather an attempt has been made to consolidate pertinent literature dealing with the toxic manifestations of Ipecac fluid extract. Ipecac contains both emetine and cephaeline and the toxicity of Ipecac fluid extract is consistent with reports on the toxicity of both compounds. The majority of the work has involved emetine since it is in higher concentration in Ipecac fluid extract than is cephaeline. Comparison of the clinical picture presented in syrup or fluid extract of Ipecac overdose and emetine toxicity in amebiasis treatment permits us to summarize the general characteristics of Ipecac alkaloid toxicity as involving primarily gastrointestinal, cardiovascular, and neuromuscular foci.