Modulation of dopamine efflux in the striatum following cholinergic stimulation of the substantia nigra in intact and pedunculopontine tegmental nucleus-lesioned rats

C. D. Blaha, P. Winn

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133 Citations (Scopus)

Abstract

The effects of microinjections of cholinergic agents into the substantia nigra pars compacta on dopamine (DA) efflux in the anterior dorsomedial striatum of urethane-anesthetized rats were investigated using in vivo chronoamperometry and intracerebral microdialysis techniques. A dose- dependent augmentation of DA efflux as evidenced by increases in the chronoamperometric signals was observed in the striatum following nigral microinjections of the cholinergic agonists nicotine or carbachol. Enhancing extracellular concentrations of ACh in the substantia nigra by intranigral infusions of the cholinesterase inhibitor neostigmine also resulted in an increase in the chronoamperometric signal corresponding to DA overflow in the striatum. These stimulatory effects of neostigmine on DA efflux in the striatum were confirmed using in vivo microdialysis. Compared to sham- operated control animals, quinolinic acid lesions of the pedunculopontine tegmental nucleus (PPTg) resulted in an attenuation of the stimulatory effects of intranigral neostigmine on DA efflux in the striatum. In contrast, these treatments resulted in an enhancement of striatal DA efflux in response to nigral infusions of the direct ACh receptor agonist nicotine. Combined, these data suggest that PPTg cholinergic neurons are indirectly involved in regulating the activity of the striatum by modulating the activity of DA neurons in the substantia nigra of the rat.

Original languageEnglish
Pages (from-to)1035-1044
Number of pages10
JournalJournal of Neuroscience
Volume13
Issue number3
Publication statusPublished - 1 Jan 1993

Keywords

  • ACh
  • chronoamperometry
  • dialysis
  • dopamine
  • pedunculopontine tegmental nucleus
  • quinolinate
  • rat
  • striatum
  • substantia nigra
  • acetylcholine
  • cholinergic receptor
  • neostigmine
  • quinolinic acid
  • amperometry
  • animal tissue
  • dose response
  • drug effect
  • nerve conduction

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