, Volume 80, Issue 3, pp 263–266 | Cite as

Changes in the sensitivity of the central α- and β-adrenergic systems during desmethylimipramine treatment as assessed by plasma growth hormone response in the baboon

  • J. R. McWilliam
  • B. S. Meldrum
  • S. A. Checkley
Original Investigations


The tricyclic antidepressant desmethylimipramine (DMI) 2.5 mg/kg IM was administered to adolescent baboons once daily for 21 days, to investigate changes in α- and β-noradrenergic function. Prior to DMI treatment, plasma growth hormone (GH) responses to the intravenous infusion of an α2-adrenergic receptor agonist, clonidine, or a β2-adrenergic antagonist, ICI 118,551, were determined. DMI, 2.5 mg/kg, administered acutely did not stimulate the release of GH (up to 4 h post injection). The GH response to clonidine was decreased 4 h after DMI, 2.5 mg/kg. Alterations in plasma GH response to clonidine and ICI 118,551 were evident during and after chronic DMI administration. The GH response to clonidine was significantly diminished after 2 days, and gradually returned to the pretreatment amplitude over 7–21 days of treatment, with an overshoot 2 days after DMI withdrawal. After 21 days of DMI administration the GH response to ICI 118,551 was significantly enhanced, and remained consistently elevated during a with-drawal period of 21 days. These changes in the response to an α-adrenergic agonist and a β-adrenergic antagonist indicate that the long term regulatory changes in receptor sensitivity, occurring between 2 and 21 days of DMI treatment, compensate for the acute effects of DMI on these responses.

Key words

Antidepressants Desmethylimipramine Clonidine Noradrenergic receptors Growth hormone responses Baboons 


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Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • J. R. McWilliam
    • 1
  • B. S. Meldrum
    • 1
  • S. A. Checkley
    • 1
  1. 1.Department of NeurologyInstitute of Psychiatry and Bethlem/Maudsley HospitalLondonUK

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