proglumide is a non-selective CCK receptor antagonist initially developed to treat stomach ulcers. I think it can decrease stomach acidity so I fear that careless non-medical use could result in increased risk of infection by foodborne bacteria. by blocking CCK in the brain, Proglumide reduces LTP and slows down neuronal activity in certain parts of the brain, particularly those involved in pain and anxiety. Proglumide has no opioid activity of its own, but by blocking CCK signalling, it can at least temporarily potentiate opioid effects and reverse tolerance. this is because CCK opposes many of the downstream sort after affects of Mu opioid activation such as analgesia and reward. actually, injecting CCK into healthy people can trigger very severe anxiety and context independent panic attacks. it should be noted that CCK also strongly suppresses dopamine release in the nucleus accumbens. this means that high CCK levels also produces dysphoria/anhedonia in addition to the anxiety. unfortunately, tolerance seems to develop to the effects of Proglumide within a few days, probably because of massive CCK Receptor upregulation. The brain probably considers CCK A very important neuropeptide given its role in facilitating fear memory and suppressing what is considered to be unnecessary reward.
Interestingly, mice that lack the circadian clock gene or the CCK gene which is under its control, produces a manic phenotype consisting of hyperactivity, decreased sleep, a lack of anxiety, increased exploration of novel environments and supersensitivity to rewards. these effects, resulting directly from the lack of CCK in the brain, are likely due to hyperactivity of the dopamine system. i’m not sure if this is a developmental affect, but I hope it isn’t. If it isn’t and the same effects occur in humans, I’ll be the 1st to volunteer for a CCK depletion/blocking drug.
