RT Journal Article
SR Electronic
T1 Altered Brain Serotonin Homeostasis and Locomotor Insensitivity to 3,4-Methylenedioxymethamphetamine (“Ecstasy”) in Serotonin Transporter-Deficient Mice
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 649
OP 655
DO 10.1124/mol.53.4.649
VO 53
IS 4
A1 Dietmar Bengel
A1 Dennis L. Murphy
A1 Anne M. Andrews
A1 Christine H. Wichems
A1 Douglas Feltner
A1 Armin Heils
A1 Rainald Mössner
A1 Heiner Westphal
A1 Klaus-Peter Lesch
YR 1998
UL http://molpharm.aspetjournals.org/content/53/4/649.abstract
AB The sodium-dependent, high affinity serotonin [5-hydroxytryptamine (5-HT)] transporter (5-HTT) provides the primary mechanism for inactivation of 5-HT after its release into the synaptic cleft. To further evaluate the function of the 5-HTT, the murine gene was disrupted by homologous recombination. Despite evidence that excess extracellular 5-HT during embryonic development, including that produced by drugs that inhibit the 5-HTT, may lead to severe craniofacial and cardiac malformations, no obvious developmental phenotype was observed in the 5-HTT−/− mice. High affinity [3H]5-HT uptake was completely absent in 5-HTT−/− mice, confirming a physiologically effective knockout of the 5-HTT gene. 5-HTT binding sites labeled with [125I]3β-(4′-iodophenyl)tropan-2β-carboxylic acid methyl ester were reduced in a gene dose-dependent manner, with no demonstrable binding in 5-HTT−/− mutants. In adult 5-HTT−/− mice, marked reductions (60–80%) in 5-HT concentrations were measured in several brain regions. While (+)-amphetamine-induced hyperactivity did not differ across genotypes, the locomotor enhancing effects of (+)-3,4-methylenedioxymethamphetamine, a substituted amphetamine that releases 5-HT via a transporter-dependent mechanism, was completely absent in 5-HTT−/− mutants. Together, these data suggest that the presence of a functional 5-HTT is essential for brain 5-HT homeostasis and for 3,4-methylenedioxymethamphetamine-induced hyperactivity.