Marihuana

Abstract

Among the drugs of abuse which are regulated under the United States Controlled Substances Act and the International Conventions, none has created more intense public debate and controversy than marihuana. Marihuana is one of many names given to the leaves and flowering tops of the plant Cannabis sativa. The plant grows in all temperate regions of this planet and has been used commercially as a source of fiber and oil. Wherever the plant grows people have learned to ingest the material for its introxicating effects. The usual routes of administration are by mouth or smoking. It has been estimated that, worldwide, more than one hundred million individuals are regular users of the plant material. However, accurate data on this situation are not available. In the United States, use data have been collected on a regular basis using two large surveys, the National Household Survey on Drug Abuse (SUBSTANCE ABUSE AND MENTAL HEALTH SERVICES AD-MINISTRATION 1994) and the Monitoring the Future Survey (JOHNSTON et al. 1994) which covers eighth, tenth, and twelfth grade students in public and private schools. Figure 1 presents the data over time for lifetime, annual, 30 day, and daily use of marihuana among high school seniors in the United States (JOHNSTON et al. 1994). As can be seen, use peaked from 1978 to 1980 and had been declining slowly up to 1992. From 1992 to 1993 there was a significant increase in all use categories. Even more disturbing was the fact that very similar trend data were reported for eighth and tenth graders. This was matched in 1992 and 1993 by a decrease in the reported "perceived risk" from use of the drug.Data from the Household Survey revealed similar findings among those 12-17 years old. It is estimated that in 1993, 600000 individuals in this age group used marihuana weekly. There was also an increase in reporting that "obtaining marihuana is fairly or very easy." These trends should give us early warning of increased future public health problems. This is especially true when one looks at the increasing concentrations of /1"tetrahydrocannabinol (/1"-THC), the psychoactive principal found in confiscated samples of the plant material. This is illustrated in Fig. 2. During the years of peak use in the United States (1976)(1977)(1978)(1979)(1980) the average /1l)-THC content of confiscated cannabis was about 1.5%. There was a steady increase C. R. Schuster et al. (eds.

The synthetic cannabinoid WIN55212‐2 decreases the intraocular pressure in human glaucoma resistant to conventional therapies

“…In addition, in laboratory animals, the IOP‐lowering effect of CP‐55940 (Pate et al., 1998) and WIN55212‐2 (Song & Slowey, 2000), two structurally distinct compounds with comparative potency consistent with their affinity for cannabinoid receptors (Compton et al., 1996), were shown to both be eliminated by the specific cannabinoid receptor antagonist SR141716A, suggesting that their effect is most likely mediated through cannabinoid receptors expressed in the eye. In addition, the finding that SR141716A per se , whether given systemically (Pate et al., 1998) or applied locally (Song & Slowey, 2000) increases IOP, is consistent with an inverse agonism (Bouaboula et al., 1997) or an antagonism by SR141716A of endogenous cannabinoid tone on IOP.…”

Selective Effects of the Endogenous Cannabinoid Arachidonylethanolamide (Anandamide) on Regional Cerebral Blood Flow in the Rat

“…Although the pharmacokinetics of THC probably are responsible for the difficulty in successfully employing the animal self-administration model of drug reinforcement, the widespread use of marijuana in society speaks to the drug's reinforcing properties (Compton et al 1996). Data reported over the years by Gardner and colleagues support the hypothesis that mesocorticolimbic dopamine pathways are activated by THC much like other drugs of abuse (Wise and Rompre 1989).…”

Regional haemodynamic responses to the cannabinoid agonist, WIN 55212‐2, in conscious, normotensive rats, and in hypertensive, transgenic rats

“…The discovery of the existence of endogenous cannabinoids (see Mechoulam et al ., 1994 ; 1998 for review), and specific receptors for them (see Pertwee, 1997 for review), has stimulated renewed interest in the possible biological role, and therapeutic potential, of drugs derived from these compounds. However, the literature to date amply illustrates the complexity of this area of research, particularly in the context of cardiovascular function (see Compton et al ., 1996 for review). For example, the effects of the cannabinoids may be influenced by the nature of the experiment ( in vitro vs in vivo ), the type of in vitro preparation (e.g., isolated mesenteric vessel vs perfused mesenteric vascular bed), and, for in vivo studies, the state of the experimental animals (pithed, anaesthetized, or conscious), their strain, and the route of administration (central vs peripheral) of the compounds.…”