Hippocampal theta rhythm is reduced by suppression of the H-current in septohippocampal GABAergic neurons.
Hippocampal learning and memory tasks are tightly coupled to the hippocampal theta rhythm, which is critically dependent on the medial septum/diagonal band of Broca (MSDB) although the underlying mechanisms remain unclear. The MSDB sends both cholinergic and GABAergic projections to the hippocampus. Here we show that: (i) septo-hippocampal GABAergic but not cholinergic neurons have a pacemaking current, the H-current, and that its selective blockade by ZD7288 reduces their spontaneous firing in rat brain slices; and (ii), local infusions of ZD7288 into the MSDB reduce exploration and sensory evoked hippocampal theta bursts in behaving rats. Thus, the H-current in septohippocampal GABAergic neurons modulates the hippocampal theta rhythm.
Xu
Changqing
C
Department of Psychiatry, CMHC 335 A, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA.
Datta
Subimal
S
Wu
Min
M
Alreja
Meenakshi
M
D000818:Animals; D018756:GABA Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020665:Septum of Brain / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013826:Theta Rhythm / Q000187:drug effects / Q000379:methods*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018756:GABA Antagonists; D011743:Pyrimidines; C082246:ICI D2788; D005680:gamma-Aminobutyric Acid