Qu Y, Villacreses N, Murphy DL, Rapoport SI. 5-HT2A/2C receptor signaling via phospholipase A2 and arachidonic acid is attenuated in mice lacking the serotonin reuptake transporter.
Psychopharmacology (Berl) 2005;
180:12-20. [PMID:
15834538 DOI:
10.1007/s00213-005-2231-5]
[Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Accepted: 12/15/2004] [Indexed: 10/25/2022]
Abstract
SUBJECTS
The serotonin reuptake transporter (SERT) helps to regulate brain serotonergic transmission and is the target of some antidepressants. To further understand SERT function, we measured a marker of regional brain phospholipase A2 (PLA2) activation in SERT knockout mice (SERT-/-) and their littermate controls (SERT+/+).
METHODS
Following administration of 1.5 mg/kg s.c. (+/-)-2,5-dimethoxy-4-iodophenyl-2-aminopropane (DOI), a 5-HT(2A/2C) receptor agonist, to unanesthetized mice injected intravenously with radiolabeled arachidonic acid (AA), PLA2 activation, represented as the regional incorporation coefficient k* of AA, was determined with quantitative autoradiography in each of 71 brain regions.
RESULTS
In SERT+/+ mice, DOI significantly increased k* in 27 regions known to have 5-HT(2A/2C) receptors, including the frontal, motor, somatosensory, pyriform and cingulate cortex, white matter, nucleus accumbens, caudate putamen, septum, CA1 of hippocampus, thalamus, and hypothalamus. In contrast, DOI did not increase k* significantly in any brain region of SERT-/- mice. Head twitches following DOI, which also were measured, were robust in SERT+/+ mice but were markedly attenuated in SERT-/- mice.
CONCLUSIONS
These results show that a lifelong elevation of the synaptic 5-HT concentration in SERT-/- mice leads to downregulation of 5-HT(2A/2C) receptor-mediated PLA2 signaling via AA and of head twitches, in response to DOI.
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