Dopamine Autoreceptor Stimulation Increases Protein Carboxyl Methylation in Striatal Slices

Marina Wolf, Robert H. Roth

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We have investigated the possibility that protein carboxyl methylation is involved in coupling dopamine autoreceptor stimulation to intracellular events such as inhibition of dopamine synthesis or release. The dopamine agonists apomorphine and TL‐99 were found to stimulate methyl ester formation in striatal slices preloaded with [3H]methionine. The stimulatory effects of apomorphine were dose‐dependent, were not due to changes in [3H]methionine uptake or S‐[3H]‐adenosyl‐methionine formation, and were blocked by the stereospecific dopamine antagonist (+)‐butaclamol. Stimulation of methyl ester formation by dopamine agonists is readily observed only when slices are prepared from rats pretreated with reserpine to deplete endogenous brain catecholamines. This suggests that in slices prepared from normal rats endogenous dopamine (DA) released during slice preparation and incubation masks the effects produced by exogenously administered dopamine agonists on protein carboxyl methylase (PCM) activity. Additional experiments suggested that the effects of apomorphine were mediated via an interaction with DA autoreceptors rather than with postsynaptic DA receptors. Destruction of monoamine neurons and their associated autoreceptors by injecting 6‐hydroxydopamine into the area of the medial forebrain bundle abolished the stimulatory effects of apomorphine on methyl ester formation in striatal slices. Furthermore the putative selective DA autoreceptor agonist EMD 23 448 was also found to stimulate methyl ester formation in striatal slices. These findings, discussed in terms of calcium‐dependent functions, support the hypothesis that PCM may be a key component in the biochemical transduction of DA autoreceptor stimulation.

Original languageEnglish (US)
Pages (from-to)291-298
Number of pages8
JournalJournal of Neurochemistry
Volume44
Issue number1
DOIs
StatePublished - Jan 1 1985
Externally publishedYes

Fingerprint

Corpus Striatum
Autoreceptors
Methylation
Apomorphine
Dopamine Agonists
Dopamine
Protein O-Methyltransferase
Esters
Proteins
Methionine
Butaclamol
Rats
Medial Forebrain Bundle
Dopamine Antagonists
Reserpine
Dopamine Receptors
Masks
Catecholamines
Neurons
Brain

Keywords

  • Brain slices
  • Dopamine autoreceptors
  • Protein carboxyl methylation

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Dopamine Autoreceptor Stimulation Increases Protein Carboxyl Methylation in Striatal Slices. / Wolf, Marina; Roth, Robert H.

In: Journal of Neurochemistry, Vol. 44, No. 1, 01.01.1985, p. 291-298.

Research output: Contribution to journalArticle

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