Serotonin Receptors and Transport Essay -- Prozac Medical Neurology Es

Serotonin Receptors and Transport Being that Fluoxetine (commercial name Prozac) basically functions as a selective reuptake inhibitor for the neurotransmitter serotonin, some discussion of this transmitter is needed before its reuptake inhibition can be addressed. Serotonin (5 hydroxytrytophan or 5HT, for short) is synthesized from the precursor amino acid tryptophan through the enzyme action of tryptophan hydroxylase (Abelson & Andrews,1997,p.794). This synthesis process occurs in the terminal boutons and the serotonin is contained in vesicles awaiting release when an action potential opens the calcium gates in the presynaptic terminal. Calcium flowing through the gate adheres to the vesicle membrane and to the terminal membrane causing the vesicle to rupture and release the transmitter across the synaptic gap (Kalat,2004,p.61). Serotonin has multiple receptor types and subtypes that are linked to many diverse neurological functions. Beginning in the 1970’s, radioligand techniques identified two broad categories of receptors, namely types 5-HT1 and 5-HT2, however, research has since identified another twelve types and associated subtypes bringing the current total to fourteen: 5HT1a,b,d,e,f, 5HT2a,b,c 5HT3, 5HT4, 5HT5a,b 5HT6, and 5HT7 (numbered suffixes represent types, lettered suffixes are subtypes). These serotonin receptor types vary by location within the brain, e.g., the highest density of 5HT1A receptors a found in the hippocampus and dorsal raphe nucleus, whereas the highest concentration of 5-HT2 sites are found in the medial prefrontal cortex (Abelson et al. 1997,p.794). Once released into the synaptic gap, serotonin is not broken down by... ... membrane (Williams et al,1998,p.3291). The exact mechanism for the inhibition is not, as yet, fully understood, however, a more complete chemical analysis of the likely processes is provided in the preceding section entitled â€Å"Specific Chemical Mechanisms.† References Abelson, J., & Andrews, P.(Eds.)(1997). Encyclopedia of Human Biology. San Diego, CA: Academy Press. Adelman, G. (Ed.)(1987). Encyclopedia of Neuroscience (Vol.2). Boston: Birkhauser. Kalat, J. W. (2004). Biological Psychology (8th ed.). Belmont, CA: Thompson-Wadsworth. Siegel, G.J., Agranoff, B.W., Albers, R.W., & Molinoff, P.B. (1994). Basic neurochemistry (5th ed.). New York: Raven Press. Shepherd, G.M. (1994). Neurobiology (3rd ed.). London: Oxford University Press. Williams, S., & Mauro, S. (1998). European journal of neuroscience, 10(10),3288-3295.