Neurotensin excitation of rat ventral tegmental neurones

Zhi-Gen Jiang, M. Pessia, R. A. North

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

1. Whole-cell patch-clamp recordings were made from ventral tegmental area neurones in rat midbrain slices in vitro. In principal cells, which are presumed to contain dopamine, neurotensin (≤ 1 μm) caused an inward current at -60 mV in thirty of forty-seven neurones and had no effect on the remainder. In secondary neurones, neurotensin caused an inward current in twelve of thirty-three cells. 2. The inward current evoked by neurotensin reached a maximum amplitude of about 80 pA, and declined over several minutes when the application was discontinued. The current was most commonly accompanied by a decrease in membrane conductance and reversed polarity at a strongly hyperpolarized potential; this reversal potential was less negative in a higher extracellular potassium concentration. Neurotensin also caused an inward current even in potassium-free internal and external solutions; this current was accompanied by a conductance increase, reversed close to 0 mV and was inhibited by reduction of the extracellular sodium concentration (from 150 to 20 mM). 3. The inward current was associated with a large increase in noise; this persisted in calcium-free solutions but was inhibited by low sodium concentration. The increase in noise was more prominent at hyperpolarized potentials. The amplitude of the unitary current underlying the increase in noise was estimated from the ratio of the variance to the mean as about 1.5 pA at -100 mV. 4. When the recording was made with an electrode containing guanosine 5'-thio-triphosphate, the steady inward current evoked by neurotensin did not reverse when the application was discontinued. When the recording electrode contained pertussis toxin, the action of neurotensin was not different although outward currents evoked by dopamine and baclofen declined with time. 5. It is concluded that neurotensin excites ventral tegmental area neurones by activating a pertussis toxin-insensitive guanosine nucleotide-binding protein. This leads to a reduction in membrane potassium conductance and an increase in membrane sodium conductance, the relative contribution of which varies from cell to cell.

Original languageEnglish (US)
Pages (from-to)119-129
Number of pages11
JournalJournal of Physiology
Volume474
Issue number1
StatePublished - 1994

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Neurotensin
Neurons
Noise
Potassium
Ventral Tegmental Area
Guanosine
Sodium
Pertussis Toxin
Membranes
Dopamine
Electrodes
Baclofen
Mesencephalon
Carrier Proteins
Nucleotides
Calcium

ASJC Scopus subject areas

  • Physiology

Cite this

Jiang, Z-G., Pessia, M., & North, R. A. (1994). Neurotensin excitation of rat ventral tegmental neurones. Journal of Physiology, 474(1), 119-129.

Neurotensin excitation of rat ventral tegmental neurones. / Jiang, Zhi-Gen; Pessia, M.; North, R. A.

In: Journal of Physiology, Vol. 474, No. 1, 1994, p. 119-129.

Research output: Contribution to journalArticle

Jiang, Z-G, Pessia, M & North, RA 1994, 'Neurotensin excitation of rat ventral tegmental neurones', Journal of Physiology, vol. 474, no. 1, pp. 119-129.
Jiang Z-G, Pessia M, North RA. Neurotensin excitation of rat ventral tegmental neurones. Journal of Physiology. 1994;474(1):119-129.
Jiang, Zhi-Gen ; Pessia, M. ; North, R. A. / Neurotensin excitation of rat ventral tegmental neurones. In: Journal of Physiology. 1994 ; Vol. 474, No. 1. pp. 119-129.
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