Departmento de Fisiologia, Division de Investigation, Facultad de Meditina UNAM, Apartado Postal 70250, Mexico 04150, D.F.Mexico;Division of Life Sciences, The University of Texas at San Antonio, San Antonio, TX 78285 USA
Abstract:
The effects of iontophoretic administration of norepinephrine (NE) and dopamine (DA) on olfactory tubercle (OT) neurons that respond to lateral hypothalamus (LH) or locus coeruleus (LC) electrical stimulation were studied. NE and DA decreased the frequency of OT neurons which were increased or decreased by the LH stimulation. An increased firing of OT neurons following NE or DA administration was less frequently observed. NE administration decreased the firing of OT neurons that responded to LC stimulation. These results suggest that the LC fibers which reach the OT use NE as a neurotransmitter. DA administration also suppressed the unitary discharge of OT neurons responding to LC stimulation. The increase in frequency of OT neurons observed following LH stimulation cannot be attributed to DA. The possibility that other suspected neural transmitters are involved in this effect is discussed.