Brain distribution serotonin receptors

Palacios, J. M., Probst, A., and Cortes, R. (1983) The distribution of serotonin receptors in the human brain High density of 3H-LSD binding sites in the raphe nuclei of the brain stem. Brain Res., 274 150-155. 

C-B is a synthetically produced hallucinogen that is most closely related to mescaline. It acts primarily on the central serotonin receptors of the brain. Serotonin is a chemical derived from the amino acid tryptophan, and widely distributed in tissues. It acts as a neurotransmitter, constricts blood vessels at injury sites, and may affect emotional states. 2C-B works by interfering with serotonin in the brain. 

Mengod, G., Nguyen, H., Le, H. et al. (1990). The distribution and cellular localization of the serotonin 1C receptor mRNA in the rodent brain examined by in situ hybridization histochemistry. Comparison with receptor binding distribution. Neuroscience 35, 577-91. 

Pompeiano, M., Palacios, J. M. Mengod, G. (1994). Distribution of the serotonin 5-HT2 receptor family mRNAs comparison between 5-HT2a and 5-HT2C receptors. Molec. Brain Res. 23, 163-78. 

Maier DL, Mani S, Donovan SL, Soppet D, Tessarollo L, McCasland JS, Meiri KF (1999) Disrupted cortical map and absence of cortical barrels in growth-associated protein (GAP)-43 knockout mice. Proc Nad Acad Sci U S A 96 9397-9402 Mansour-Robaey S, Mechawar N, Radja F, Beaulieu C, Descarries L (1998) Quantified distribution of serotonin transporter and receptors during the postnatal development of the rat barrel field cortex. Brain Res Dev Brain Res 107 159-163 Manuck SB, Flory JD, Ferrell RE, Dent KM, Mann JJ, Muldoon MF (1999) Aggression and anger-related traits associated with a polymorphism of the tryptophan hydroxylase gene. Biol Psychiatry 45 603-614... 

Miquel MC, Doucet E, Boni C (1991) Central serotonin 1A receptor respective distributions of encoding mRNA, receptor protein and binding sites by in situ hybridization histochemistry, radioimmunohistochemistry and autoradiographic mapping in the rat brain. Neurochem Int 19 453-465... 

Thus, virtually all side effects of the SSRIs can be understood as undesirable actions of serotonin in undesirable pathways at undesirable receptor subtypes. This appears to be the cost of doing business, as it is not possible for a systemically administered SSRI to act only at the desirable receptors in the desirable places it must act everywhere it is distributed, which means all over the brain and all over the body. Fortunately, SSRI side effects are more of a nuisance than a danger, and they generally attenuate over time, although they can cause an important subset of patients to discontinue an SSRI prematurely. 

Thus, there were serotonin 1 receptors, and then there were 1 and 2 receptors, and then la and lb and 2a and 2b receptors, and on and on. These are called 5-HT receptors, since the chemical name for serotonin is 5-hy-droxytryptamine, and the scientist would never want to let the layman know just what he is talking about. DOI has been synthesized with a variety of radioactive iodine isotopes in it, and these tools have been of considerable value in mapping out its brain distribution. And by extrapolation, the possible localization of other psychedelic compounds that cannot be so easily labelled. A small neurochemical research company on the East Coast picked up on these properties of DOI, and offered it as a commercial item for research experiments. But I doubt that they are completely innocent of the fact that DOI is an extremely potent psychedelic and that it is still unrecognized by the Federal drug laws since, in their most recent catalog, the price had almost doubled and a note had been added to the effect that telephone orders cannot be accepted for this compound. 

Huang J, Spier AD, Pickel VM. 5-HT3A receptor subunits in the rat medial nucleus of the solitary tract subcellular distribution and relation to the serotonin transporter. Brain Res 2004 1028 156-169. 

Vamas K, Halldin C, Hall H. Autoradiographic distribution of serotonin transporters and receptor subtypes in human brain. Hum Brain Mapping 2004 22 246-260. 

Pasqualetti M, Nardi I, Ladinsky H, Marazziti D, Cassano GB. Comparative anatomical distribution of serotonin 1 A, IDa and 2A receptor mRNAs in human brain postmortem. Mol Brain Res 1996 39 223-233. 

Pasqualetti M, Ori M, Castagna M, Marazziti D, Cassano GB, Nardi I. Distribution and cellular localization of the serotonin type 2C receptor messenger RNA in human brain. Neuroscience 1999 92 601-611. 

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