Neuropeptide Y potentiates via Y2-receptors the inhibitory effect of noradrenaline in rat locus coeruleus neurones.

Intracellular recordings were carried out in a pontine slice preparation of the rat brain containing the locus coeruleus (LC). Pressure application of noradrenaline with various pulse durations inhibited the spontaneous frequency of action potentials and hyperpolarized the membrane. Neuropeptide Y (NPY), its C-terminal fragment NPY (16-36) and peptide YY (PYY), at a concentration of 0.1 mumol/l all, potentiated the effect of noradrenaline, while [Leu31, Pro34]NPY (0.1 mumol/l) was inactive. These results are compatible with the presence of Y2-type NPY-receptors at the cell somata of LC neurones.