Neurotensin enhances glutamatergic EPSCs in VTA neurons by acting on different neurotensin receptors

Publication date: Available online 18 August 2015 Source:Peptides Author(s): Poulomee Bose, Pierre-Paul Rompré, Richard A. Warren Neurotensin (NT) is an endogenous neuropeptide that modulates dopamine and glutamate neurotransmission in several limbic regions innervated by neurons located in the ventral tegmental area (VTA). While several studies showed that NT exerted a direct modulation on VTA dopamine neurons less is known about its role in the modulation of glutamatergic neurotransmission in this region. The present study was aimed at characterising the effects of NT on glutamate-mediated responses in different populations of VTA neurons. Using whole cell patch clamp recording technique in horizontal rat brain slices, we measured the amplitude of glutamatergic excitatory post-synaptic currents (EPSCs) evoked by electrical stimulation of VTA afferents before and after application of different concentrations of NT1-13 or its C-terminal fragment, NT8-13. Neurons were classified as either Ih + or Ih − based on the presence or absence of a hyperpolarisation activated cationic current (Ih). We found that NT1-13 and NT8-13 produced comparable concentration dependent increase in the amplitude of EPSCs in both Ih + and Ih − neurons. In Ih + neurons, the enhancement effect of NT8-13 was blocked by both antagonists, while in Ih − neurons it was blocked by the NTS1/NTS2 antagonist, SR142948A, but not the preferred NTS1 antagonist, SR48692. In as much as Ih − neurons...
Source: Peptides - Category: Biochemistry Source Type: research