Regionally selective effects of intracerebral dopamine infusion on sensorimotor gating of the startle reflex in rats
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Systemic administration of dopamine (DA) agonists markedly disrupts sensorimotor gating in rats as measured by prepulse inhibition (PPI) of the acoustic startle response. A qualitatively similar, but quantitatively weaker disruption of PPI follows DA infusion into the nucleus accumbens (NAC). The present study was designed to determine whether forebrain DA terminal fields other than the NAC contribute to the DAergic modulation of PPI. PPI was impaired significantly after infusion of DA (0–40 µg) into the NAC or anteromedial striatum, but not after DA infusion into the orbital cortex or posterolateral striatum. DA infusion into the amygdala also disrupted PPI, but this disruption was accompanied by a dose-dependent decrease in startle amplitude. These results suggest that DA overactivity in the both NAC and anteromedial striatum contribute to the gating-disruptive effects of systemically administered DA agonists, and that DA overactivity in mesocortical, mesoamygdaloid and “non-limbic” mesostriatal DA systems are not major substrates for a DAergic modulation of PPI.
Key wordsAcoustic startle response Amygdala Dopamine Nucleus accumbens Orbital cortex Prepulse inhibition Sensorimotor gating Striatum
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- Davis M, Mansbach RS, Swerdlow NR, Braff DL, Geyer MA (1990) Apomorphine disrupts the inhibition of acoustic startle induced by weak prepulses in rats. Psychopharmacology 102:1–4Google Scholar
- Grillon C, Ameli R, Braff DL (1991) Sensorimotor gating deficits in schizophrenia: Replication and extension using the startle response. Biol Psychiatry 29:164AGoogle Scholar
- Heimer L, Wilson RD (1975) The subcortical projections of the allocortex: Similarities in the neural associations of the hippocampus, the piriform cortex and the neocortex. In: Santini M (ed) Golgi Centennial Symposium Proceedings. Raven Press, New York, pp 177–193Google Scholar
- Paxinos G, Watson C (1986) The rat brain in stereotaxic coordinates. Academic Press, AustraliaGoogle Scholar
- Pellegrino LJ, Pellegrino AS, Cushman AJ (1979) A stereotaxic atlas of the rat brain. Plenum Press, New YorkGoogle Scholar
- Swerdlow NR, Caine B, Geyer MA (1992b) Sensorimotor gating of the startle reflex is mediated by ventral pallidal efferents to the pedunculopontine nucleus. Abstr Soc Neurosci (in press)Google Scholar
- Wong D, Wagner H, Tune L, Dannals R, Pearlson G, Links J, Tamminga C, Broussolle E, Ravert H, Wilson A, Toung J, Malat J, Williams J, O'Tuama L, Snyder S, Kuhar M, Gjedde A (1986) Positron emission tomography reveals elevated D2 dopamine receptors in drug-naive schizophrenics. Science 234:1558–1563PubMedGoogle Scholar
- Young KA, Randall PK, Wilcox RE (1990) Effect of thalamic microinjection of apomorphine and muscimol on the acoustic startle response and other behaviors. Abstr Soc Neurosci 16:426Google Scholar