Adrenergic receptor function in panic disorder. I. Platelet alpha 2 receptors: Gi protein coupling, effects of imipramine, and relationship to treatment outcome.
Neuropsychopharmacology
; 20(2): 162-76, 1999 Feb.
Article
en En
| MEDLINE
| ID: mdl-9885796
ABSTRACT
Various studies suggest alpha 2-adrenergic receptor (alpha 2AR) dysregulation in panic disorder (PD). Platelet alpha 2-AR exist in high- and low-conformational states as a function of their coupling to Gi protein. alpha 2AR coupling is important in signal transduction and is modulated by antidepressants. alpha 2AR density in the high- and low-conformational states, agonist affinity, and coupling efficiency were investigated in 21 healthy controls, 21 drug-free PD patients, and eight imipramine-treated patients using norepinephrine displacement of 3H-yohimbine binding. Percentage of receptors in the high-conformational state (%RH) and the ratio of the agonist dissociation constant to the receptor in the low-/high-conformational state (KL/KH), calculated from displacement experiments, were used as coupling indices. Patients had high alpha 2AR density in both conformational states. %RH and KL/KH ratio were significantly different, particularly in patients with Hamilton scale for depression (HAMD) scores > or = 15. Imipramine treatment (29 weeks) had no effect on alpha 2AR density or coupling, despite improvement in anxiety ratings. High pretreatment alpha 2AR density and coupling predicted low severity of anxiety after treatment. Increased alpha 2AR density and abnormal coupling may represent an adaptive mechanism or trait marker in PD.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Plaquetas
/
Trastorno de Pánico
/
Receptores Adrenérgicos alfa 2
/
Subunidades alfa de la Proteína de Unión al GTP Gi-Go
/
Imipramina
/
Antidepresivos Tricíclicos
Tipo de estudio:
Prognostic_studies
Límite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
Neuropsychopharmacology
Asunto de la revista:
NEUROLOGIA
/
PSICOFARMACOLOGIA
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos