Fentanyl decreases beta-CIT binding to the dopamine transporter.
Evidence from animal studies suggest that centrally acting opiates increase synaptic dopamine (DA) concentration. However, the interaction between mu-opioid receptors and the DA system is unclear. We report here an effect of fentanyl on striatal [123I]beta-CIT binding to the DA transporter in a patient and in rats. A female patient underwent [123I]beta-CIT single-photon emission tomography (SPET) study after intrathecal injection of fentanyl for her back pain. After a 2-week drug-free period, the SPET study was repeated. In the experimental study, male Wistar rats were treated with fentanyl either acutely (50 micrograms/kg, i.p.) before imaging study or subacutely for 4 days (10 micrograms/kg, twice a day, i.p.). Brain planar imaging was performed at 3.5 hours after an intravenous injection of [123I]beta-CIT with gamma camera with a pinhole collimator. In a female patient, [123I]beta-CIT binding in the basal ganglia was decreased by 37% during fentanyl as compared to the binding after 2-week drug-free period. Similarly in rats, acute fentanyl treatment decreased [123I]beta-CIT binding to the striatum by 30% as compared to that of with the control rats. After subacute administration of fentanyl, no significant difference was observed compared to the control group. According to the present data, fentanyl decreases [123I]beta-CIT binding in the basal ganglia both in human and rats, suggesting that opiates possibly directly affect DA reuptake.
Bergström
K A
KA
Department of Clinical Physiology, Kuopio University Hospital, Finland. Kim.Bergstrom@uku.fi
Jolkkonen
J
J
Kuikka
J T
JT
Akerman
K K
KK
Viinamäki
H
H
Airaksinen
O
O
Länsimies
E
E
Tiihonen
J
J
D000328:Adult; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001479:Basal Ganglia / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives* / Q000378:metabolism; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D005283:Fentanyl / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D015899:Tomography, Emission-Computed, Single-Photon
D000701:Analgesics, Opioid; D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine; D005283:Fentanyl