title: Intracellular mechanisms modulating gamma band activity in the pedunculopontine nucleus (PPN).
abstract: The pedunculopontine nucleus is a part of the reticular activating system, and is active during waking and REM sleep. Previous results showed that all PPN cells tested fired maximally at gamma frequencies when depolarized. This intrinsic membrane property was shown to be mediated by high-threshold N- and P/Q-type Ca(2+) channels. Recent studies show that the PPN contains three independent populations of neurons which can generate gamma band oscillations through only N-type channels, only P/Q-type channels, or both N- and P/Q-type channels. This study investigated the intracellular mechanisms modulating gamma band activity in each population of neurons. We performed in vitro patch-clamp recordings of PPN neurons from Sprague-Dawley rat pups, and applied 1-sec ramps to induce intrinsic membrane oscillations. Our results show that there are two pathways modulating gamma band activity in PPN neurons. We describe populations of neurons mediating gamma band activity through only N-type channels and the cAMP/PKA pathway (presumed "REM-on" neurons), through only P/Q-type channels and the CaMKII pathway (presumed "Wake-on" neurons), and a third population which can mediate gamma activity through both N-type channels and cAMP/PK and P/Q-type channels and CaMKII (presumed "Wake/REM-on" neurons). These novel results suggest that PPN gamma oscillations are modulated by two independent pathways related to different Ca(2+) channel types.
authors.affiliation: Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
authors.forename: Brennon R
authors.initials: BR
authors.lastname: Luster
authors.affiliation: IFIBYNE-CONICET, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Urbano
authors.affiliation: Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, Arkansas GarciaRillEdgar@uams.edu.
authors.forename: Edgar
authors.initials: E
authors.lastname: Garcia-Rill
mesh_terms: D000818:Animals; D020864:Calcium Channels, N-Type / Q000378:metabolism*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D065818:Gamma Rhythm; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D045042:Pedunculopontine Tegmental Nucleus / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015290:Second Messenger Systems
chemical_list: D020864:Calcium Channels, N-Type; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2
keywords: Arousal; Ca2+ channels; CaMKII; N‐Type; P/Q‐type; cAMP‐PKA; gamma oscillations