Regular paper
The vesicular monoamine transporter is not regulated by dopaminergic drug treatments

https://doi.org/10.1016/0014-2999(95)00594-3Get rights and content

Abstract

The number of neuronal synaptic vesicular monoamine transporters (vesicular monoamine transporter type 2; VMAT2) has been recently proposed as an index of monoamine presynaptic terminal density. The present study investigated the possible regulation of the vesicular monoamine transporter. Rats were treated for 2 weeks with drugs known to influence dopaminergic neurotransmission, including those commonly used in the treatment of Parkinson's disease. Autoradiographic assays were performed using [3H]methoxytetrabenazine, [3H]raclopride, and [3H]WIN 35,428 ([3H]2β-carbomethoxy-3β-(4-fluorophenyl)tropane) to measure vesicular monoamine transporter, dopamine D2 receptor and synaptic plasma membrane dopamine re-uptake site bindings, respectively. None of the drug treatments significantly modified levels of vesicular monoamine transporter binding. In contrast, both dopamine D2 receptors and dopamine re-uptake sites were altered by some of the treatment regimens. These data extend preliminary results that suggest the vesicular monoamine transporter is not easily regulated and confirm the plasticity of dopamine D2 receptors and the dopamine re-uptake site. Measures of striatal vesicular monoamine transporter density may, thus, provide objective estimates of monoaminergic innervation in neurodegenerative diseases, unaffected by the use of symptomatic therapies.

References (39)

  • R.K. Mishra et al.

    Chemical lesion and drug induced supersensitivity and subsensitivity of caudate dopamine receptor

    Life Sci.

    (1978)
  • L. Naudon et al.

    Short-term treatments with haloperidol or bromocriptine do not alter the density of the monoamine vesicular transporter

    Neurosci. Lett.

    (1994)
  • L.G. Sharpe et al.

    Withdrawal of repeated cocaine decreases autoradiographic [3H]mazindol-labelling of dopamine transporter in rat nucleus accumbens

    Eur. J. Pharmacol.

    (1991)
  • T.M. Vander Borght et al.

    [3H]Methoxytetrabenazine: a high specific activity ligand for estimating monoaminergic neuronal integrity

    Neuroscience

    (1995)
  • H.L. Wiener et al.

    Chronic l-deprenyl induced up-regulation of the dopamine uptake carrier

    Eur. J. Pharmacol.

    (1989)
  • S. Yamada et al.

    Chronic treatment with haloperidol modifies the sensitivity of autoreceptors that modulate dopamine release in rat striatum

    Eur. J. Pharmacol.

    (1993)
  • P. Allard et al.

    Unaltered [3H]GBR-12935 binding after chronic treatment with deopamine active drugs

    Psychopharmacology

    (1990)
  • S.M. Aquilonius et al.

    In vivo evaluation of striatal dopamine re-uptake site using C-11-nomifensine and positron emission tomography

    Acta Neurol. Scand.

    (1987)
  • D.R. Burt et al.

    Antischizophrenic drugs: chronic treatment elevates dopamine receptor binding in brain

    Science

    (1977)
  • Cited by (0)

    View full text