Fig. 1.

Effect of the selective Y₁ agonist [F7,P34]pNPY as well as neuropeptide Y (NPY) alone and in combination with selective A₁R agonist N⁶-cyclopentyladenosine (CPA) on the amplitude of postsynaptic potentials (PSPs) evoked by electrical field stimulation (0.2 Hz, 2 ms) in layer I of the rat cingulate cortex (Sichardt et al., unpublished results). Intracellular recordings were performed in rat brain slices using glass microelectrodes placed in pyramidal cells of layer V. a [F7,P34]pNPY superfused for 5 min inhibits reversibly the PSPs by 34.6 ± 8%. Y₁ antagonist BIBP3226 itself reduces the PSP by 23 ± 10%, whereas [F7,P34]pNPY has no inhibitory effect in the presence of the antagonist. b NPY depresses PSPs by 28.6 ± 0.7%. The combined superfusion of NPY and CPA resulted in an additional depression of the PSPs by 48.1 ± 5%. The depressant effects of the two agonists were reversible during washout. Data are expressed as mean ± SEM from n = 3 independent experiments. *p < 0.05 significant vs control; ^#p < 0.05 significant vs NPY alone