Neurotensin modulation of spontaneous EPSCs in the nucleus accumbens of Lewis and Fischer 344 rats.

Fischer 344 (F344) and Lewis (LEW) rats are inbred strains that are differentially sensitive to drugs of abuse and that respond differently to the endogenous neuropeptide neurotensin (NT). To understand the mechanisms involved we used whole cell patch clamp recording technique to study the effects of an equimolar concentration of NT and its active analog, d-Tyr[11]neurotensin (d-NT), on the amplitude and frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in nucleus accumbens medium spiny (MS) neurons in brain slices. NT and d-NT produced an increase in the amplitude but not in the frequency of sEPSCs in all neurons tested in both F344 and LEW rats.

Electrical stimulation of thalamic Nucleus Submedius inhibits responses of spinal dorsal horn neurons to colorectal distension in the rat.

In 78 halothane-anesthetized rats, we characterized the responses of single neurons in the dorsal horn of L(6)-S(1) spinal segments to a noxious visceral stimulus (colorectal balloon distension, CRD), and studied the effects of focal electrical stimulation of Nucleus Submedius (Sm) on these responses using standard extracellular microelectrode recording techniques. A total of 102 neurons were isolated on the basis of spontaneous activity. Eighty (78%) responded to CRD, of which 70% had excitatory and 30% had inhibitory responses.