From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Fri Aug 02 2002 - 12:41:26 MDT
Smoke pot!
Nature has an interesting article
Nature 418:530-534 (2002)
Marsicano, G. et al.
The endogenous cannabinoid system controls extinction of aversive memories
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v418/n6897/full/nature00839_fs.html
summarized by Pankaj Sah:
Neurobiology: Never fear, cannabinoids are here
Nature 418:488-489 (2002)
Extracts:
> A large body of work has established that a small, almond-shaped region
> in the brain, the amygdala, is crucial in acquiring and, possibly,
> storing the memory of conditioned fear. It is thought that, at the
> cellular and molecular level, this learned behaviour requires neurons in
> the basolateral part of the amygdala, and changes in the strength of
> their connection with other neurons ('synaptic plasticity') that depend
> on the NMDA receptor, which responds to the neurotransmitter glutamate.
>
> The extinction of aversive memories also involves the basolateral
> amygdala, but the cellular and molecular details are less clear. [snip]
>
> Marsicano et al. now propose just such a mechanism, which involves the
> endocannabinoids anandamide and 2-arachidonylglycerol, and their CB1
> receptors. These receptors are some of the most abundant neuromodulatory
> receptors in the central nervous system and are expressed at high levels
> in the limbic system, cerebellum and basal ganglia8. The classical
> behavioural effects of exogenous cannabinoids -- such as sedation and
> memory changes -- have been correlated with the presence of CB1 receptors
> in the limbic system and striatum.
>
> After engineering mice to lack the CB1 receptor, Marsicano et al. first
> showed that although these animals could learn and later recall the
> association of a tone with a foot shock, they could not extinguish the
> memory. A drug that antagonizes the CB1 receptor similarly prevented
> extinction in wild-type mice. The authors then found that during the
> extinction protocol (exposure to the tone alone), the levels of both
> anandamide and 2-arachidonylglycerol were raised in the basolateral
> amygdala in mutant and normal mice. This implies that a process
> involving activation of the CB1 receptors by endocannabinoids is
> essential in the extinction of conditioned fear.
So that explains why potheads are so laid back. They've forgotten
all of the stuff that constitutes the hazards in life that one
*shouldn't* be laid back about.
Robert
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