An alternative for PET imaging the 5-HT2A receptor is the
[11C]volinanserin (MDL-100,907) radioligand.
18F-altanserin and 3H-volinanserin have shown very comparable binding.
Both altanserin and MDL 100,907 are 5-HT2A receptor antagonists.
[18F]-setoperone can also be used in PET.
The altanserin PET scan shows high binding in neocortex.
The cerebellum is often regarded as a region with no specific 5-HT2A binding and the brain region is used as a reference in some studies, even though an autoradiography study has found nonnegligible levels of 5-HT2A binding in the human cerebellum,
and another type of study have observed strong immunoreaction against 5-HT2A receptor protein in rat Purkinje cells.
In the table below is an overview of the results of altanserin binding seen in human PET-studies.
A consistent finding across altanserin studies has been that the binding decreases with age.
This is in line with in vitro studies of the 5-HT2A receptor,
as well as PET studies with other radioligands that binds to the receptor.
The result for recovered bulimia-type anorexia nervosa
is in line with a SPECT study of anorexia nervosa patients, that found a decrease in frontal, occipital and parietal cortices.
The results of PET studies of the 5-HT2A in depression has been mixed.
Altanserin binding has also been examine in twins, where one study showed higher correlation between monozygotic twin pairs than between dizygotic twin pairs, giving evidence that the binding is "strongly genetically determined".
The sequence starts with the alkylation of pyrrolidine nitrogen in (1) with 2-bromoethylamine. Reaction of the primary amine in the product (2) with thiophosgene leads to the isothiocyanate derivative (3). Reaction of that reactive intermediate with methyl anthranilate (4) leads initially to the transient addition product (5). This then undergoes the customary internal ester exchange reaction to form the heterocyclic ring. There is thus obtained the serotonin antagonist altanserin (6).
^Lemaire C, Cantineau R, Guillaume M, Plenevaux A, Christiaens L (1991). "Fluorine-18-altanserin: a radioligand for the study of serotonin receptors with PET: radiolabeling and in vivo biologic behavior in rats". J. Nucl. Med. 32 (12): 2266–72. PMID1744713.
^ abKristiansen H, Elfving B, Plenge P, Pinborg LH, Gillings N, Knudsen GM (2005). "Binding characteristics of the 5-HT2A receptor antagonists altanserin and MDL 100907". Synapse. 58 (4): 249–57. doi:10.1002/syn.20205. PMID16206185.
^ abAudenaert K, Van Laere K, Dumont F, Vervaet M, Goethals I, Slegers G, Mertens J, van Heeringen C, Dierckx RA (2003). "Decreased 5-HT2a receptor binding in patients with anorexia nervosa". J. Nucl. Med. 44 (2): 163–9. PMID12571204.
^Sadzot B, Lemaire C, Maquet P, Salmon E, Plenevaux A, Degueldre C, Hermanne JP, Guillaume M, Cantineau R, Comar D, et al. (September 1995). "Serotonin 5HT2 receptor imaging in the human brain using positron emission tomography and a new radioligand, [18F]altanserin: results in young normal controls". Journal of Cerebral Blood Flow and Metabolism. 15 (5): 787–797. doi:10.1038/jcbfm.1995.99. PMID7673371.
^Smith GS, Price JC, Lopresti BJ, Huang Y, Simpson N, Holt D, Mason NS, Meltzer CC, Sweet RA, Nichols T, Sashin D, Mathis CA (1998). "Test-retest variability of serotonin 5-HT2A receptor binding measured with positron emission tomography and [18F]altanserin in the human brain". Synapse. 30 (4): 380–392. doi:10.1002/(SICI)1098-2396(199812)30:4<380::AID-SYN5>3.0.CO;2-U.
^Eastwood SL, Burnet PW, Gittins R, Baker K, Harrison PJ (November 2001). "Expression of serotonin 5-HT2A receptors in the human cerebellum and alterations in schizophrenia". Synapse. 42 (2): 104–114. doi:10.1002/syn.1106. PMID11574947.
^Mark A. Mintun, Yvette I. Sheline, Stephen M. Moerlein, Andrei G. Vlassenko, Abraham Z. Snyder (February 2004). "Decreased hippocampal 5-HT2A receptor binding in major depressive disorder: in vivo measurement with [18F]altanserin positron emission tomography". Biological Psychiatry. 55 (3): 217–224. doi:10.1016/j.biopsych.2003.08.015. PMID14744461.
^René Hurlemann, Andreas Matusch, Kai-Uwe Kuhn, Julia Berning, David Elmenhorst, Oliver Winz, Heike Kolsch, Karl Zilles, Michael Wagner, Wolfgang Maier Andreas Bauer (January 2008). "5-HT2A receptor density is decreased in the at-risk mental state". Psychopharmacology. 195 (4): 579–590. doi:10.1007/s00213-007-0921-x. PMID17899021.
^René Hurlemann, Christian Boy, Philipp T. Meyer, Harald Scherk, Michael Wagner, Hans Herzog, Heinz H. Coenen, Kai Vogeley, Peter Falkai, Karl Zilles, Wolfgang Maier Andreas Bauer (December 2005). "Decreased prefrontal 5-HT2A receptor binding in subjects at enhanced risk for schizophrenia". Anatomy and Embryology. 210 (5–6): 519–523. doi:10.1007/s00429-005-0036-2. PMID16187138.
^Rosier A, Dupont P, Peuskens J, Bormans G, Vandenberghe R, Maes M, de Groot T, Schiepers C, Verbruggen A, Mortelmans L (November 1996). "Visualisation of loss of 5-HT2A receptors with age in healthy volunteers using [18F]altanserin and positron emission tomographic imaging". Psychiatry Research. 68 (1): 11–22. doi:10.1016/S0925-4927(96)02806-5. PMID9027929.
^Carolyn Cidis Meltzer, Gwenn Smith, Julie C. Price, Charles F. Reynolds III, Chester A. Mathis, Phil Greer, Brian Lopresti, Mark A. Mintun, Bruce G. Pollock, Doron Ben-Eliezer, Michael N. Cantwell, Walter Kaye, Steven T. DeKosky (November 1998). "Reduced binding of [18F]altanserin to serotonin type 2A receptors in aging: persistence of effect after partial volume correction". Brain Research. 813 (1): 167–171. doi:10.1016/S0006-8993(98)00909-3. PMID9824691.
^K. H. Adams, Pinborg, Svarer, Hasselbalch, Holm, Haugbøl, Madsen, Frøkjaer, Martiny, Paulson, Knudsen (March 2004). "A database of [18F]-altanserin binding to 5-HT2A receptors in normal volunteers: normative data and relationship to physiological and demographic variables". NeuroImage. 21 (3): 1105–1113. doi:10.1016/j.neuroimage.2003.10.046. PMID15006678.