From: rpattree2@gmail.com   
      
   arijuana's anxiety relief effects: Receptors found in emotional hub of brain   
   Date:   
   March 6, 2014   
   Source:   
   Vanderbilt University Medical Center   
   Summary:   
   Cannabinoid receptors, through which marijuana exerts its effects, have been   
   found in a key emotional hub in the brain involved in regulating anxiety and   
   the flight-or-fight response. This is the first time cannabinoid receptors   
   have been identified in    
   the central nucleus of the amygdala in a mouse model.   
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   Sachin Patel, M.D., Ph.D., right, Teniel Ramikie, and colleagues found   
   cannabinoid receptors in a part of the brain involved in regulating anxiety.   
   Credit: Joe Howell   
   [Click to enlarge image]   
   An international group led by Vanderbilt University researchers has found   
   cannabinoid receptors, through which marijuana exerts its effects, in a key   
   emotional hub in the brain involved in regulating anxiety and the   
   flight-or-fight response.   
      
      
      
   This is the first time cannabinoid receptors have been identified in the   
   central nucleus of the amygdala in a mouse model, they report in the current   
   issue of the journal Neuron.   
   The discovery may help explain why marijuana users say they take the drug   
   mainly to reduce anxiety, said Sachin Patel, M.D., Ph.D., the paper's senior   
   author and professor of Psychiatry and of Molecular Physiology and Biophysics.   
   Led by first author Teniel Ramikie, a graduate student in Patel's lab, the   
   researchers also showed for the first time how nerve cells in this part of the   
   brain make and release their own natural "endocannabinoids."   
   The study "could be highly important for understanding how cannabis exerts its   
   behavioral effects," Patel said. As the legalization of marijuana spreads   
   across the country, more people -- and especially young people whose brains   
   are still developing --    
   are being exposed to the drug.   
   Previous studies at Vanderbilt and elsewhere, Patel said, have suggested the   
   following:   
   The natural endocannabinoid system regulates anxiety and the response to   
   stress by dampening excitatory signals that involve the neurotransmitter   
   glutamate.   
   Chronic stress or acute, severe emotional trauma can cause a reduction in both   
   the production of endocannabinoids and the responsiveness of the receptors.   
   Without their "buffering" effect, anxiety goes up.   
   While marijuana's "exogenous" cannabinoids also can reduce anxiety, chronic   
   use of the drug down-regulates the receptors, paradoxically increasing   
   anxiety. This can trigger "a vicious cycle" of increasing marijuana use that   
   in some cases leads to    
   addiction.   
   In the current study, the researchers used high-affinity antibodies to "label"   
   the cannabinoid receptors so they could be seen using various microscopy   
   techniques, including electron microscopy, which allowed very detailed   
   visualization at individual    
   synapses, or gaps between nerve cells.   
   "We know where the receptors are, we know their function, we know how these   
   neurons make their own cannabinoids," Patel said. "Now can we see how that   
   system is affected by ... stress and chronic (marijuana) use? It might   
   fundamentally change our    
   understanding of cellular communication in the amygdala."   
   Story Source:   
   The above story is based on materials provided by Vanderbilt University   
   Medical Center. The original article was written by Bill Snyder. Note:   
   Materials may be edited for content and length.   
   Journal Reference:   
   Teniel S. Ramikie, Rita Nyilas, Rebecca J. Bluett, Joyonna C. Gamble-George,   
   Nolan D. Hartley, Ken Mackie, Masahiko Watanabe, István Katona, Sachin Patel.   
   Multiple Mechanistically Distinct Modes of Endocannabinoid Mobilization at   
   Central Amygdala    
   Glutamatergic Synapses. Neuron, 2014; 81 (5): 1111 DOI: 10.1016/   
   .neuron.2014.01.012   
   Cite This Page:   
   MLA APA Chicago   
   Vanderbilt University Medical Center. "Marijuana's anxiety relief effects:   
   Receptors found in emotional hub of brain." ScienceDaily. ScienceDaily, 6   
   March 2014.    
      
      
      
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