title: Bidirectional modulation of hippocampal gamma (20-80 Hz) frequency activity in vitro via alpha(α)- and beta(β)-adrenergic receptors (AR).
abstract: Noradrenaline (NA) in the hippocampus plays an important role in memory function and has been shown to modulate different forms of synaptic plasticity. Oscillations in the gamma frequency (20-80 Hz) band in the hippocampus have also been proposed to play an important role in memory functions and, evidence from both in vitro and in vivo studies, has suggested this activity can be modulated by NA. However, the role of different NA receptor subtypes in the modulation of gamma frequency activity has not been fully elucidated. We have found that NA (30 μM) exerts a bidirectional control on the magnitude of kainate-evoked (50-200 nM) gamma frequency oscillations in the cornu Ammonis (CA3) region of the rat hippocampus in vitro via activation of different receptor subtypes. Activation of alpha-adrenergic receptors (α-AR) reduced the power of the gamma frequency oscillation. In contrast, activation of beta-adrenergic receptors (β-AR) caused an increase in the power of the gamma frequency oscillations. Using specific agonists and antagonists of AR receptor subtypes we demonstrated that these effects are mediated specifically via α1A-AR and β1-AR subtypes. NA activated both receptor subtypes, but the α1A-AR-mediated effect predominated, resulting in a reversible suppression of gamma frequency activity. These results suggest that NA is able to differentially modulate on-going gamma frequency oscillatory activity that could result in either increased or decreased information flow through the hippocampus.
authors.affiliation: Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK; Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, BCMT-T728, Houston, TX 77030, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Haggerty
authors.forename: V
authors.initials: V
authors.lastname: Glykos
authors.forename: N E
authors.initials: NE
authors.lastname: Adams
authors.forename: F E N
authors.initials: FE
authors.lastname: Lebeau
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D018663:Adrenergic Agents / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001703:Biophysics; D004347:Drug Interactions; D004558:Electric Stimulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005583:Fourier Analysis; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D010507:Periodicity; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013997:Time Factors
chemical_list: D018663:Adrenergic Agents; D018690:Excitatory Amino Acid Agonists; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D007608:Kainic Acid
keywords: 6-FNE; 6-fluronorepinephrine; ACSF; ANOVA; BTX; CA1; CA3; EPSPs; IPSPs; IQR; ISO; LC; LTD; LTP; NA; PLC; RI; SEM; alpha-adrenergic receptor; analysis of variance; artificial cerebrospinal fluid; beta-adrenergic receptor; betaxolol; cornu ammonis 1; cornu ammonis 3; excitatory post-synaptic potentials; gamma oscillation; hippocampus; inhibitory post-synaptic potentials; inter-quartile range; isoproterenol; locus coereleus; long-term depression; long-term potentiation; noradrenaline; phospholipase C; rat; rhythmicity index; standard error of the mean; α-AR; β-AR