Cholinergic modulation of purinergic and GABAergic co-transmission at in vitro hypothalamic synapses.
The lateral hypothalamus (LH) is an important center for the integration of autonomic and limbic information and is implicated in the modulation of visceral motor and sensory pathways, including those underlying feeding and arousal behaviors. LH neurons in vitro release both ATP and GABA. The control of ATP and GABA co-transmission in LH may underlie the participation of LH in basic aspects of arousal and reinforcement. LH neurons receive cholinergic input from the pedunculopontine and laterodorsal tegmental nuclei as well as from cholinergic interneurons within the LH per se. This study presents evidence for nicotinic acetylcholine receptor (nAChR)-mediated enhancement of GABAergic, but not of purinergic, transmission despite the co-transmission of ATP and GABA at LH synapses in vitro. Facilitation of GABAergic transmission by nicotine is inhibited by antagonists of (alphabeta)*-containing nAChRs, but is unaffected by an alpha7-selective antagonist, consistent with a nAChR-mediated enhancement of GABA release mediated by non-alpha7-containing nAChRs. Activation of muscarinic ACh receptors enhances the release of ATP while concomitantly depressing GABAergic transmission. The independent modulation of ATP/GABAergic transmission may provide a new level of synaptic flexibility in which individual neurons utilize more than one neurotransmitter but retain independent control over their synaptic activity.
Jo
Young-Hwan
YH
Department of Anatomy and Cell Biology in the Center for Neurobiology and Behavior, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA.
Role
Lorna W
LW
D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D002642:Chick Embryo; D018678:Cholinergic Agents / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D009116:Muscarine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011976:Receptors, Muscarinic / Q000187:drug effects; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018678:Cholinergic Agents; D018721:Muscarinic Agonists; D018722:Nicotinic Agonists; D011976:Receptors, Muscarinic; D011983:Receptors, Purinergic; D005680:gamma-Aminobutyric Acid; D009538:Nicotine; D009116:Muscarine; D000255:Adenosine Triphosphate