rats PO is 800 mg/kg, 1270 mg/kg depending upon vehicle [4]. This is comparatively weak compared to cocaine. The LD50 for cocaine is 95.1 mg/kg, Swiss mice IP [5]. The weak marijuana LD50 is often used to argue for cannabis' comparative safely and general benign nature as a drug. We will discuss respiratory depression and the myriad of indirect ways with which cannabis can cause harm below. There is much focus on today's high THC concentration. It is common to find much more THC and much less CBD per plant [6,7]. The problem of pesticide-contaminated marijuana also requires more research [8]. Pesticide has been detected on cannabis plants intended for commercial sale. Smoked marijuana reaches Cmax much faster than orally consumed cannabis. Smoked marijuana enters the bloodstream quickly, exerts its effects via CB 1 CB 2 receptors in the central nervous system and peripheral nervous system respectively. Marijuana constricts blood vessels, affecting the cardiovascular system, pulmonary system and brain vasculature. It also binds to CB 1 receptors that are in the brain, in areas central to cognitive performance such as the hippocampus, prefrontal cortex, amygdala, and striatum. It's been demonstrated that the physiology of experienced smokers differs from that of new smokers. THC maximum concentrations (Cmax) in blood were higher in frequent smokers compared to occasional smokers. A study reports that, because THC has a high degree of liphillicity, its half-life (T1/2) is 7 days and can be detected for up to 30 days [9].
Marijuana, opiates and the gateway effectThere are many new concerns regarding today's potent marijuana. Some of the old concerns that applied to less potent marijuana are being revisited. When we think back to the '70s and '80 to the days of less potent marijuana, we could not have envisioned a rampant and extensive heroin and opiate crisis among adolescents and young adults, including in suburban areas. The gateway hypothesis describes the potential for marijuana to open the door to harder drugs. It is still hotly debated [10]. However science is starting to catch up. First, there has been much work on marijuana addiction alone [11]. Scientists at NIDA have been working hard to understand marijuana's reward system. Second, credible research has shown marijuana leads to an increase in prescription drug abuse by young people, such as oxycontin [12]. We know from research [13] and accounts from heroin addicts themselves, that once hooked on oxycontin, kids will resort to less expensive heroin to achieve their opiate high. Now investigators have demonstrated that, by dosing adolescent rats with THC, allowing these F 1 animals to breed at maturity, the offspring's mRNA expressed an altered reward system and receptors in the striatum. Alterations in cannabinoid, dopamine, and glutamatergic receptors in dorsal striatum has implications for compulsive and goal directed behaviors such as drug seeking and drug addiction. In fact, offspring of animals exposed to THC, showed increased self-administration and...