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Neurotensin-induced dopamine release in vivo and in vitro from substantia nigra and nucleus caudate.

Publication ,  Journal Article
Faggin, BM; Zubieta, JK; Rezvani, AH; Cubeddu, LX
Published in: J Pharmacol Exp Ther
February 1990

We compared the dopamine (DA) releasing effects of neurotensin (NT) from cell bodies (substantia nigra) and nerve terminals (nucleus caudate). In rats implanted with push-pull cannula, NT induced DA release from substantia nigra and nucleus caudate. NT was more potent in releasing DA from the substantia nigra than from the nucleus caudate (EC50%, 1.1 microM in substantia nigra and 9.8 microM in nucleus caudate). In vitro, in superfused rabbit brain slices, NT enhanced the depolarization-evoked release of DA and exerted a direct releasing effect. The latter was greater in the substantia nigra, and the former in the nucleus caudate. The direct releasing effect of NT was not inhibited, but enhanced by nomifensine (3 microM). Sulpiride, a D2 DA receptor antagonist, failed to modify NT-induced DA release; in addition, NT did not affect the inhibition of DA and acetylcholine release produced by LY-171555, a D2 DA agonist. In both the substantia nigra and the nucleus caudate, desensitization to the releasing effect of NT was observed, either after 2.5, 5, or 10 min of exposure to the peptide. A synergistic interaction on DA release was observed between NT and potassium (K+), and between NT and electrical stimulation. Greater synergism was observed with high extracellular K+. Pretreatment of striatal slices with 15 mM K+ produced a 9-fold enhancement of NT-induced DA release. When K+ (25 mM, 2 min) was given together with NT there was a 2- to 3-fold increase in DA release compared to the release evoked by K+ in the absence of NT.(ABSTRACT TRUNCATED AT 250 WORDS)

Duke Scholars

Published In

J Pharmacol Exp Ther

ISSN

0022-3565

Publication Date

February 1990

Volume

252

Issue

2

Start / End Page

817 / 825

Location

United States

Related Subject Headings

  • Sulpiride
  • Substantia Nigra
  • Receptors, Dopamine D2
  • Receptors, Dopamine
  • Rats, Inbred Strains
  • Rats
  • Rabbits
  • Quinpirole
  • Potassium
  • Pharmacology & Pharmacy
 

Citation

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Faggin, B. M., Zubieta, J. K., Rezvani, A. H., & Cubeddu, L. X. (1990). Neurotensin-induced dopamine release in vivo and in vitro from substantia nigra and nucleus caudate. J Pharmacol Exp Ther, 252(2), 817–825.
Faggin, B. M., J. K. Zubieta, A. H. Rezvani, and L. X. Cubeddu. “Neurotensin-induced dopamine release in vivo and in vitro from substantia nigra and nucleus caudate.J Pharmacol Exp Ther 252, no. 2 (February 1990): 817–25.
Faggin BM, Zubieta JK, Rezvani AH, Cubeddu LX. Neurotensin-induced dopamine release in vivo and in vitro from substantia nigra and nucleus caudate. J Pharmacol Exp Ther. 1990 Feb;252(2):817–25.
Faggin, B. M., et al. “Neurotensin-induced dopamine release in vivo and in vitro from substantia nigra and nucleus caudate.J Pharmacol Exp Ther, vol. 252, no. 2, Feb. 1990, pp. 817–25.
Faggin BM, Zubieta JK, Rezvani AH, Cubeddu LX. Neurotensin-induced dopamine release in vivo and in vitro from substantia nigra and nucleus caudate. J Pharmacol Exp Ther. 1990 Feb;252(2):817–825.

Published In

J Pharmacol Exp Ther

ISSN

0022-3565

Publication Date

February 1990

Volume

252

Issue

2

Start / End Page

817 / 825

Location

United States

Related Subject Headings

  • Sulpiride
  • Substantia Nigra
  • Receptors, Dopamine D2
  • Receptors, Dopamine
  • Rats, Inbred Strains
  • Rats
  • Rabbits
  • Quinpirole
  • Potassium
  • Pharmacology & Pharmacy