Premium
Monoamines block kainate‐ and carbachol‐induced γ‐oscillations but augment stimulus‐induced γ‐oscillations in rat hippocampus in vitro
Author(s) -
Wójtowicz Anna Maria,
van den Boom Leander,
Chakrabarty Arnab,
Maggio Nicola,
Haq Rizwan ul,
Behrens Christoph J.,
Heinemann Uwe
Publication year - 2009
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20508
Subject(s) - carbachol , kainate receptor , chemistry , forskolin , monoamine neurotransmitter , neuroscience , agonist , serotonin , hippocampal formation , medicine , endocrinology , receptor , biology , nmda receptor , ampa receptor , biochemistry
Monoamines are implicated in a cognitive processes in a variety of brain regions, including the hippocampal formation, where storage and retrieval of information are facilitated by synchronous network activities. We have investigated the effects of norepinephrine, serotonin, and dopamine on carbachol‐, kainate‐, and stimulus‐induced hippocampal γ‐oscillations employing combined extra‐ and intracellular recordings. Monoamines dose‐dependently and reversibly suppressed kainate‐ and carbachol‐induced γ‐oscillations while increasing the frequency. The effect of serotonin was mimicked by fenfluramine, which releases serotonin from presynaptic terminals. Forskolin also suppressed kainate‐ and carbachol‐induced γ‐oscillations. This effect was mimicked by 8‐Br‐cAMP and isoproterenol, an agonist of noradrenergic β‐receptor suggesting that the monoamines‐mediated suppression of these oscillations could involve intracellular cyclic adenosine 3′,5′‐cyclic monophosphate (AMP). By contrast, stimulus‐induced γ‐oscillations were dose‐dependently augmented in power and duration after monoamines application. Intracellular recordings from pyramidal cells revealed that monoamines prolonged the stimulus‐induced depolarization and membrane potential oscillations. Stimulus‐induced γ‐oscillations were also suppressed by isoproterenol, the D1 agonist SKF‐38393 forskolin, and 8‐Br‐cAMP. This suggests that the augmentation of stimulus‐induced γ‐oscillations by monoamines involves—at least in part—different classes of cells than in case of carbachol‐ and kainate‐induced γ‐oscillations. © 2009 Wiley‐Liss, Inc.