Measuring endogenous changes in serotonergic neurotransmission in humans: a [11C]CUMI-101 PET challenge study

Sudhakar Selvaraj; Federico Turkheimer; Lula Rosso; Paul Faulkner; Elias Mouchlianitis; Jonathan P. Roiser; Philip McGuire; Philip J. Cowen; Oliver Howes

Measuring endogenous changes in serotonergic neurotransmission in humans: a [11C]CUMI-101 PET challenge study

Sudhakar Selvaraj, Federico Turkheimer, Lula Rosso, Paul Faulkner, Elias Mouchlianitis, Jonathan P. Roiser, Philip McGuire, Philip J. Cowen, Oliver Howes

Research output: Contribution to journal › Article › peer-review

Abstract

Serotonin (5-HT) neurotransmission is implicated in cognitive and emotional processes and a number of neuropsychiatric disorders. The use of positron emission tomography (PET) to measure ligand displacement has allowed estimation of endogenous dopamine release in the human brain; however, applying this methodology to assess central 5-HT release has proved more challenging. The aim of this study was to assess the sensitivity of a highly selective 5-HT1A partial agonist radioligand [11C]CUMI-101 to changes in endogenous 5-HT levels induced by an intravenous challenge with the selective 5-HT re-uptake inhibitor (SSRI), citalopram, in healthy human participants. We studied 15 healthy participants who underwent PET scanning in conjunction with [11C]CUMI-101 after receiving an intravenous infusion of citalopram 10 mg or placebo in a double-blind, crossover, randomized design. Regional estimates of binding potential (BPND) were obtained by calculating total volumes of distribution (VT) for presynaptic dorsal raphe nucleus (DRN) and postsynaptic cortical regions. Relative to placebo, citalopram infusion significantly increased [11C]CUMI-101 BPND at postsynaptic 5-HT1A receptors in several cortical regions, but there was no change in binding at 5-HT1A autoreceptors in the DRN. Across the postsynaptic brain regions, citalopram treatment induced a mean 7% in [11C]CUMI-101 BPND (placebo 1.3 (0.2); citalopram 1.4 (0.2); paired t-test P=0.003). The observed increase in postsynaptic [11C]CUMI-101 availability identified following acute citalopram administration could be attributable to a decrease in endogenous 5-HT availability in cortical terminal regions, consistent with preclinical animal studies, in which acute administration of SSRIs decreases DRN cell firing through activation of 5-HT1A autoreceptors to reduce 5-HT levels in postsynaptic regions. We conclude that [11C]CUMI-101 may be sensitive to changes in endogenous 5-HT release in humans.

Original language	English
Pages (from-to)	1254-1260
Number of pages	16
Journal	MOLECULAR PSYCHIATRY
Volume	17
Publication status	Published - 5 Jun 2012

Keywords

antidepressants
citalopram
5HT1A receptor
neuroimaging
positron emission tomography
serotonin

Cite this

@article{b9d694e9622f4936895f6a1e3422351e,

title = "Measuring endogenous changes in serotonergic neurotransmission in humans: a [11C]CUMI-101 PET challenge study",

abstract = "Serotonin (5-HT) neurotransmission is implicated in cognitive and emotional processes and a number of neuropsychiatric disorders. The use of positron emission tomography (PET) to measure ligand displacement has allowed estimation of endogenous dopamine release in the human brain; however, applying this methodology to assess central 5-HT release has proved more challenging. The aim of this study was to assess the sensitivity of a highly selective 5-HT1A partial agonist radioligand [11C]CUMI-101 to changes in endogenous 5-HT levels induced by an intravenous challenge with the selective 5-HT re-uptake inhibitor (SSRI), citalopram, in healthy human participants. We studied 15 healthy participants who underwent PET scanning in conjunction with [11C]CUMI-101 after receiving an intravenous infusion of citalopram 10 mg or placebo in a double-blind, crossover, randomized design. Regional estimates of binding potential (BPND) were obtained by calculating total volumes of distribution (VT) for presynaptic dorsal raphe nucleus (DRN) and postsynaptic cortical regions. Relative to placebo, citalopram infusion significantly increased [11C]CUMI-101 BPND at postsynaptic 5-HT1A receptors in several cortical regions, but there was no change in binding at 5-HT1A autoreceptors in the DRN. Across the postsynaptic brain regions, citalopram treatment induced a mean 7% in [11C]CUMI-101 BPND (placebo 1.3 (0.2); citalopram 1.4 (0.2); paired t-test P=0.003). The observed increase in postsynaptic [11C]CUMI-101 availability identified following acute citalopram administration could be attributable to a decrease in endogenous 5-HT availability in cortical terminal regions, consistent with preclinical animal studies, in which acute administration of SSRIs decreases DRN cell firing through activation of 5-HT1A autoreceptors to reduce 5-HT levels in postsynaptic regions. We conclude that [11C]CUMI-101 may be sensitive to changes in endogenous 5-HT release in humans.",

keywords = "antidepressants, citalopram, 5HT1A receptor, neuroimaging, positron emission tomography, serotonin",

author = "Sudhakar Selvaraj and Federico Turkheimer and Lula Rosso and Paul Faulkner and Elias Mouchlianitis and Roiser, {Jonathan P.} and Philip McGuire and Cowen, {Philip J.} and Oliver Howes",

year = "2012",

month = jun,

day = "5",

language = "English",

volume = "17",

pages = "1254--1260",

journal = "MOLECULAR PSYCHIATRY",

issn = "1359-4184",

publisher = "Nature Publishing Group",

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T1 - Measuring endogenous changes in serotonergic neurotransmission in humans: a [11C]CUMI-101 PET challenge study

AU - Selvaraj, Sudhakar

AU - Turkheimer, Federico

AU - Rosso, Lula

AU - Faulkner, Paul

AU - Mouchlianitis, Elias

AU - Roiser, Jonathan P.

AU - McGuire, Philip

AU - Cowen, Philip J.

AU - Howes, Oliver

PY - 2012/6/5

Y1 - 2012/6/5

N2 - Serotonin (5-HT) neurotransmission is implicated in cognitive and emotional processes and a number of neuropsychiatric disorders. The use of positron emission tomography (PET) to measure ligand displacement has allowed estimation of endogenous dopamine release in the human brain; however, applying this methodology to assess central 5-HT release has proved more challenging. The aim of this study was to assess the sensitivity of a highly selective 5-HT1A partial agonist radioligand [11C]CUMI-101 to changes in endogenous 5-HT levels induced by an intravenous challenge with the selective 5-HT re-uptake inhibitor (SSRI), citalopram, in healthy human participants. We studied 15 healthy participants who underwent PET scanning in conjunction with [11C]CUMI-101 after receiving an intravenous infusion of citalopram 10 mg or placebo in a double-blind, crossover, randomized design. Regional estimates of binding potential (BPND) were obtained by calculating total volumes of distribution (VT) for presynaptic dorsal raphe nucleus (DRN) and postsynaptic cortical regions. Relative to placebo, citalopram infusion significantly increased [11C]CUMI-101 BPND at postsynaptic 5-HT1A receptors in several cortical regions, but there was no change in binding at 5-HT1A autoreceptors in the DRN. Across the postsynaptic brain regions, citalopram treatment induced a mean 7% in [11C]CUMI-101 BPND (placebo 1.3 (0.2); citalopram 1.4 (0.2); paired t-test P=0.003). The observed increase in postsynaptic [11C]CUMI-101 availability identified following acute citalopram administration could be attributable to a decrease in endogenous 5-HT availability in cortical terminal regions, consistent with preclinical animal studies, in which acute administration of SSRIs decreases DRN cell firing through activation of 5-HT1A autoreceptors to reduce 5-HT levels in postsynaptic regions. We conclude that [11C]CUMI-101 may be sensitive to changes in endogenous 5-HT release in humans.

AB - Serotonin (5-HT) neurotransmission is implicated in cognitive and emotional processes and a number of neuropsychiatric disorders. The use of positron emission tomography (PET) to measure ligand displacement has allowed estimation of endogenous dopamine release in the human brain; however, applying this methodology to assess central 5-HT release has proved more challenging. The aim of this study was to assess the sensitivity of a highly selective 5-HT1A partial agonist radioligand [11C]CUMI-101 to changes in endogenous 5-HT levels induced by an intravenous challenge with the selective 5-HT re-uptake inhibitor (SSRI), citalopram, in healthy human participants. We studied 15 healthy participants who underwent PET scanning in conjunction with [11C]CUMI-101 after receiving an intravenous infusion of citalopram 10 mg or placebo in a double-blind, crossover, randomized design. Regional estimates of binding potential (BPND) were obtained by calculating total volumes of distribution (VT) for presynaptic dorsal raphe nucleus (DRN) and postsynaptic cortical regions. Relative to placebo, citalopram infusion significantly increased [11C]CUMI-101 BPND at postsynaptic 5-HT1A receptors in several cortical regions, but there was no change in binding at 5-HT1A autoreceptors in the DRN. Across the postsynaptic brain regions, citalopram treatment induced a mean 7% in [11C]CUMI-101 BPND (placebo 1.3 (0.2); citalopram 1.4 (0.2); paired t-test P=0.003). The observed increase in postsynaptic [11C]CUMI-101 availability identified following acute citalopram administration could be attributable to a decrease in endogenous 5-HT availability in cortical terminal regions, consistent with preclinical animal studies, in which acute administration of SSRIs decreases DRN cell firing through activation of 5-HT1A autoreceptors to reduce 5-HT levels in postsynaptic regions. We conclude that [11C]CUMI-101 may be sensitive to changes in endogenous 5-HT release in humans.

KW - antidepressants

KW - citalopram

KW - 5HT1A receptor

KW - neuroimaging

KW - positron emission tomography

KW - serotonin

M3 - Article

SN - 1359-4184

VL - 17

SP - 1254

EP - 1260

JO - MOLECULAR PSYCHIATRY

JF - MOLECULAR PSYCHIATRY

ER -