Differential Effects of Neuropeptide Y Type 2 Receptor Activation on Responses of Rat Ventral Posteromedial Thalamus Neurons to Surround Vibrissae and Trigeminal Subnucleus Interpolaris Stimulation

Single cell recording, receptive field analysis, and microejection techniques were used to evaluate the effects of neuropeptide Y (NPY) type 2 (Y2) receptor activation on the responses of vibrissae-sensitive ventral posteromedial thalamic (VPM) neurons. Activation of this receptor with the C-terminal fragment, NPY[13-36] had no significant effect on responses evoked by deflection of principal or surround vibrissae or electrical stimulation of the trigeminal principal sensory nucleus. However, it did significantly decrease (p < 0.01) responses evoked by electrical stimulation of subnucleus interpolaris (SpI) by a mean (+/- standard error) of -31.0 +/- 8.7%). The finding that responses to surround vibrissa stimulation were not significantly decreased by a manipulation that did significantly attenuate SpI- evoked responses suggests that this nucleus is not the sole source of surround vibrissae input to VPM neurons.