SSRI antidepressants do not confound single photon emission computed tomography (SPECT) imaging studies using the alpha4beta2 nicotinic acetylcholine receptor [123I]5-I-A85380 ligand: in vivo and in vitro evidence.
OBJECTIVE
In clinical molecular imaging the interaction between antidepressant medication and SPECT ligands is a significant potential confound. This study measured nAChR availability, as determined by SPECT imaging, on and off selective serotonin reuptake inhibitors in first episode depressed patients.


METHODS
Five patients in their first episode of major depressive disorder (MDD) on a single SSRI underwent [(123)I]5-I-A85380- SPECT neuroimaging prior to stopping their medication and again 6 weeks following medication cessation. Autoradiography of post mortem brain tissue with [(125)I]5-I-A85380 in the presence or absence of four commonly prescribed antidepressants was also assessed.


RESULTS
SSRI antidepressants did not affect the relative binding availability of alpha4beta2 nicotinic acetylcholine receptors for the [(123)I]5-I-A85380 ligand in vivo. Radioligand binding in vitro was unaffected by a single, high pharmacological concentration of antidepressants.


CONCLUSIONS
SPECT imaging studies using [(123)I]5-I-A85380 to measure alpha4beta2 nAChR availability in depressed patients are unlikely to be confounded to a major degree by concurrent antidepressant medication.
Cavanagh
Jonathan
J
Sackler Institute of Psychobiological Research, Division of Community Based Sciences, Faculty of Medicine, University of Glasgow, Southern General Hospital, Glasgow, G51 4TF, UK. j.cavanagh@clinmed.gla.ac.uk
Patterson
James
J
Pimlott
Sally
S
Wyper
David
D
Dewar
Deborah
D
D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology* / Q000627:therapeutic use; D001345:Autoradiography; D001384:Azetidines / Q000494:pharmacology*; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects; D015283:Citalopram / Q000494:pharmacology / Q000627:therapeutic use; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D005260:Female; D005473:Fluoxetine / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011725:Pyridines / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000378:metabolism; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D018687:Antidepressive Agents, Second-Generation; D001384:Azetidines; D015283:Citalopram; D005473:Fluoxetine; D011725:Pyridines; D011978:Receptors, Nicotinic; D017367:Selective Serotonin Reuptake Inhibitors; C426745:5-iodo-3-(2-azetidinylmethoxy)pyridine; C403531:nicotinic receptor alpha4beta2