Paragigantocellularis stimulation induces beta-adrenergic hippocampal potentiation.
The nucleus paragigantocellularis (PGi) is the major excitatory glutamatergic input to the locus coeruleus (LC). Glutamate activation of the LC has previously been shown to produce beta-adrenergic-dependent potentiation of the perforant path- (PP) evoked population spike in the dentate gyrus (DG). The present study asks if electrical stimulation of the PGi, by activating the LC endogenously, can produce a parallel beta-receptor-dependent potentiation of the PP-evoked population spike. An optimal interstimulus interval (ISI) was determined for PGi-PP stimulation in urethane-anesthetized rats and propranolol was used to assess the role of noradrenergic beta-receptors. PGi stimulation potentiated the PP-evoked population spike at an optimal ISI of 30 ms. The population synaptic response slope and spike latency were not affected. Propranolol blocked the PGi-induced potentiation, as would be expected for beta-receptor-dependent modulation. The parallels between PGi- and LC-induced effects on the PP-evoked population spike suggest PGi stimulation offers an alternate method of LC activation for studies of LC's role in behavior.
Babstock
D M
DM
Department of Psychology, Memorial University of Newfoundland, St. John's, Canada.
Harley
C W
CW
D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D008125:Locus Coeruleus / Q000033:anatomy & histology / Q000502:physiology*; D008526:Medulla Oblongata / Q000033:anatomy & histology / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology*
D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D009638:Norepinephrine