Erowid References Database
Seeman P, Westman K, Coscena D, Warsh J.
“Serotonin Receptors in Hippocampus and Frontal Cortex”.
The inhibition by various serotonin agonists and antagonists of the binding of 3 nM 3H-d-LSD, 1.7 nM 3Hserotonin and 0.22 nM H-piperone to homogenates of calf hippocampus and frontal cortex was studied. The 50 0nhibitory concentrations (IC50) for these drugs versus 3HLSD binding had similar values, to and correlated with corresponding IC50 values versus a 3Hserotonin binding in the hippocampus, suggesting that 3HLSD and IH50 serotonin label similar sites in the region to the calf frontal cortex, serotonin revealed a biphasic inhibition 3H-d-LSD binding and the tryptamines-inhibited over a concentration range of 10,000-fold. The IC25 versus 3H-d-LSD binding correlated with the IC50 values versus 3H serotonin, but did not correlate with the IC50 values versus 3H-spiperone. These datn suggest thit 3H-d-LSD bound to more than one serotonin site in the calf frontal cortex and that 3Hspiperone bound to a separate serotonergic site. Scatchard of the binding for the three 3H-ligands indicated that in the calf frontal cortex the density of 3H-d-LSD, sites was approximately equal to the sum of the densities for 3Hserotonin (S-1 sites) and 3H-spiperone (S-2, stes), two weeks after serotonin-depleting radiofrequency heat lesions of the midbrain dorsal and meidal raphe nuclei in rats, both 3Hserotonin and 3H-LSD showed enhanced binding in the hippocampus. These data support previous suggestions that supersensitivity develops specifically in serotonin receptors following afferent denervation.
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