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The endocannabinoid system refers a specific type of retrograde signaling that regulates neuronal excitability in wide array or neuronal tissues including the cerebellum, hippocampus, and cereberal cortex [1] [2] [3] In these neuronal circuits, stimulation of the post-synaptic neuron by its ligand causes a retrograde suppression of neurotransmitter release from the pre-synaptic neuron. This is achieved in two ways. First, after stimulation, the post-synaptic neuron rapidly synthesizes anandamide, an endocannabinoid, from a cell membrane-resident phospholipid, N-arachidonoyl phosphatidylethanolamine. [4]. After endocannabinoid release, anandamide binds to CB1 receptors on pre-synaptic neurons preventing the firing an action potential, thus temporarily halting neurotransmitter release. In this way, a post-synaptic neuron can tightly regulate its excitability by modulating the activity of pre-synaptic neurons. The endocannabinoid system is thought important in long-term potentiation and memory[5] [6], motor learning [7], and synaptic plasticity [8].

Contents 1 Endocannabinoid System 2 ECS changes induced by Cannabis Consumption 2.1 Memory 2.2 Appetite 3 ECS and female reproduction

Those who use cannabis are familiar with its appetite-enhancing effects. Emerging data suggests that THC act via CB1 receptors on hypothalamic nuclei, thus directly increasing appetite[9][10].

It is thought that hypothalamic neurons tonically produce endocannabinoids that work to tightly regulate hunger. Interestingly, the amount of endocannabinoids produced is inversely correlated with the amount of leptin in the blood[11]. For example, mice without leptin not only become massively obese but have higher-than-normal levels of hypothalamic endocannabinoids [12]. Similarly, when these mice were treated with an endocannabinoid antagonist, such as Rimonabant, food intake was reduced[13]. While there is need for more research, these results (and others) suggest that exogenous cannabinoids (as from smoking marijuana) in the hypothalamus activates a pathway responsible for food-seeking behavior [14].

The developing embryo expresses cannabinoid receptors early in development that are responsive to anandamide which is secreted in the uterus. This signaling is important in regulating the timing of embryonic implantation and uterine receptivity. In mice, it has been shown that anandamide modulates the probability of implantation to the uterine wall . For example, in humans, the likelihood of miscarriage increases if uterine anandamide levels are too high or low [15]. These results suggest that proper intake of exogenous cannabinoids (e.g. marijuana) can decrease the likelihood for pregnancy[16][17].