Posted by Cam W. on May 16, 2001, at 10:46:37
Scott - The latest issue of Neuropsychopharmacology has and article by Y.Levkovitz on TMS ("Transcranial Magnetic Stimulation and Antidepressant Drugs Share Simular Cellular Effects in Rat Hippocampus"). It seems that TMS, desipramine and miaserin all increase serotonergic neurotransmission and reverse hippocampal atrophy:
"The present sudy demonstrated a similarity of effects of chronic TMS and two typical antidepressants, miaserin and desipramine, on the reactivity of the hippocampus to stimulation of the perforant path [to the dentate gyrus], its main excitatory afferent pathway arriving from the entorhinal cortex."
"Although these treatments did not affect basal EPSP slopes and population spike size, their effects on paired-pulse and frequency-dependent inhibition indicate that TMS, as do desipramine and mianserin, share a primary action on local inhibitory interneurons activated in these stimulation protocols ."
"Our results on the reduction in efficacy of FFA [test drug fenfluramine] can be reconciled with the suggested increase in serotonergic neurotransmission following chronic antidepressant treatment (Blier and deMontigny 1994). If, indeed, the chronic treatment causes a continuous release of serotonin and/or increase in receptor sensitivity, we can expect that added release, evoked by FFA, will not be effective. Moreover, the chronic increase in serotonin release can have an indirect, downregulating action on the receptor for FFA. Finally, the effects of the antidepressants to increase excitability of the hippocampus are consistent with this possibility."
Alas, Neuropsychopharmacology is no longer free, but if you haven't signed up to the free trial of Neuroscion ( http://www.neuroscion.com ) I would recommend doing so. The allow you to print 25 articles from the Elsevier Science Journals (eg. Cognition, Brain Research Reviews, European Neuropsychopharmaology, Schizophrenia Research, Journal of Psychiatric Research, Psychoneuroendocrinology, etc). I also recommend browsing the journals list rather than setting up a library of journal articles. This is very much a "geek site" but I have printed of some facinating studies (it is where I got Phil Seeman's (guy who came up with receptor site theory) paper on the mechanism of action of atypical antipsychotics (ie 5-HT2A receptors do not have any antipsychotic action and the low D2 binding of these agents is due to the drugs tweaking, rather than irreversibly binding to, D2 receptors).
Anyway Scott, check out Neuroscion because I know that you are as big a geek as me. A word of warning, read the titles and abstracts carefully or you may miss some ground breaking and facinating papers.
;^)
Take care - Cam
poster:Cam W.
thread:63213
URL: http://www.dr-bob.org/babble/20010515/msgs/63213.html