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Quantification of mu and non-mu opiate receptors in temporal lobe epilepsy using PET

Discussion in 'Pharmacology' started by Forthesevenlakes, Jul 16, 2006.

  1. Forthesevenlakes

    Forthesevenlakes Platinum Member

    Reputation Points:
    Feb 26, 2006
    regarding a thread SWIM posted here regarding a spiritual experience on opiates, he decided to try to look for a connection between opioid receptors, responses to opiates, etc. and religious experience. one candidate for religious and spiritual experience could be activity in the temporal lobe of the human brain. people with temporal lobe epilepsy experience overactivity in this brain region, and some report feelings of a divine presence, intense reverence of a higher power, etc., which are also characteristic of drug-induced spiritual experiences. here's what I found, please add articles if you have anything to contribute!

    from Annals of Neurology (abstract):

    Ann Neurol. 1991 Jul;30(1):3-11. Related Articles, Links
    [SIZE=+1]Quantification of mu and non-mu opiate receptors in temporal lobe epilepsy using positron emission tomography.

    Mayberg HS, Sadzot B, Meltzer CC, Fisher RS, Lesser RP, Dannals RF, Lever JR, Wilson AA, Ravert HT, Wagner HN Jr, et al.

    Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.

    Alterations in a variety of neurotransmitter systems have been identified in experimental models of epilepsy and in brain tissue from patients with intractable temporal lobe seizures. The availability of new high-affinity radioligands permits the study of some neuroreceptors in vivo with positron emission tomography (PET). We previously characterized the in vivo binding of 11C-carfentanil, a potent and selective mu opiate receptor agonist, and described increases in 11C-carfentanil binding in the temporal neocortex of patients with unilateral temporal lobe epilepsy. These studies have been extended to 11C-diprenorphine, which labels mu, kappa, and delta opiate receptor subtypes. Paired measurements of opiate receptor binding were performed with PET using 11C-carfentanil and 11C-diprenorphine in patients with unilateral temporal lobe seizures. Carfentanil binding, reflecting changes in mu opiate receptors, was increased in the temporal neocortex and decreased in the amygdala on the side of the epileptic focus. Diprenorphine binding, reflecting mu as well as non-mu opiate subtypes, was not significantly different among regions in the focus and nonfocus temporal lobes. Regional glucose metabolism, measured using 18F-2-fluoro-2-deoxyglucose, was decreased in the mesial and lateral aspects of the temporal lobe ipsilateral to the epileptogenic focus. The variation in pattern of carfentanil and diprenorphine binding supports a differential regulation of opiate subtypes in unilateral temporal lobe epilepsy. The second article can be found here (abstract)
    Neuropsychobiology Vol. 37, No. 4, 1998
    Pathological Regional Cerebral Blood Flow in Opiate-Dependent Patients during Withdrawal: A HMPAO-SPECT Study
    P. Danosa, S. Kasperb, F. Grünwaldc, E. Klemmc, C. Krappeld, K. Broiche, G. Höflichd, B. Overbeckc, H.J. Biersackc, H.J. Möllerf

    The aims of the present study were to investigate regional cerebral blood flow (rCBF) in heroin-dependent patients during withdrawal and to assess the relation between these changes and duration of heroin consumption and withdrawal data. The rCBF was measured using brain SPECT with 99mTc-HMPAO in 16 heroin-dependent patients during heroin withdrawal. Thirteen patients received levomethadone at the time of the SPECT scans. The images were analyzed both visually and quantitatively. A total of 21 hypoperfused brain regions were observed in 11 of the 16 patients. The temporal lobes were the most affected area, hypoperfusions of the right and left temporal lobe were observed in 5 and 5 patients, respectively. Three of the patients had a hypoperfusion of the right frontal lobe, 2 patients showed perfusion defects in the left frontal lobe, right parietal lobe and left parietal lobe. The results of the quantitative assessments of the rCBF were consistent with the results of the qualitative findings. The stepwise regression analysis showed a significant positive correlation (r = 0.54) between the dose of levomethadone at the time of the SPECT scan and the rCBF of the right parietal lobe. Other significant correlations between clinical data and rCBF were not found. The present results suggest brain perfusion abnormalities during heroin withdrawal in heroin-dependent patients, which are not due to the conditions of withdrawal.

    So, while the evidence collected by me thus far is somewhat meager, it does suggest that:

    1. use of opiates can cause changes, sometimes lengthy changes, in the temporal lobe.
    2. these changes directly pertain to the binding of opiates to opiate receptors.

    so, perhaps SWIM's bizarre experience mentioned at the beginning of this post is not just an anomaly caused by doing to many psychedelics in the past, but was a mystical drug experience in and of itself triggered not by psychedelics, but by opiates. Any feedback?