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Muscarinic and nicotinic responses in the developing pedunculopontine nucleus (PPN).
- Source :
-
Brain research [Brain Res] 2007 Jan 19; Vol. 1129 (1), pp. 147-55. Date of Electronic Publication: 2006 Dec 06. - Publication Year :
- 2007
-
Abstract
- The pedunculopontine nucleus (PPN), the cholinergic arm of the reticular activating system (RAS), is known to modulate waking and rapid eye movement (REM) sleep. REM sleep decreases between 10 and 30 days postnatally in the rat, with the majority occurring between 12 and 21 days. We investigated the possibility that changes in the cholinergic, muscarinic and/or nicotinic, input to PPN neurons could explain at least part of the developmental decrease in REM sleep. We recorded intracellularly from PPN neurons in 12-21 day rat brainstem slices maintained in artificial cerebrospinal fluid (aCSF) and found that application of the nicotinic agonist 1,1-dimethyl-4-phenyl-piperazinium iodide (DMPP) depolarized PPN neurons early in development, then hyperpolarized PPN neurons by day 21. Most of the effects of DMPP persisted following application of the sodium channel blocker tetrodotoxin (TTX), and in the presence of glutamatergic, serotonergic, noradrenergic and GABAergic antagonists, but were blocked by the nicotinic antagonist mecamylamine (MEC). The mixed muscarinic agonist carbachol (CAR) hyperpolarized all type II (A current) PPN cells and depolarized all type I (low threshold spike-LTS current) and type III (A+LTS current) PPN cells, but did not change effects during the period known for the developmental decrease in REM sleep. The effects of CAR persisted in the presence of TTX but were mostly blocked by the muscarinic antagonist atropine (ATR), and the remainder by MEC. We conclude that, while the nicotinic inputs to the PPN may help modulate the developmental decrease in REM sleep, the muscarinic inputs appear to modulate different types of cells differentially.
- Subjects :
- Action Potentials drug effects
Action Potentials physiology
Aging physiology
Animals
Animals, Newborn
Cell Differentiation physiology
Muscarinic Agonists pharmacology
Muscarinic Antagonists pharmacology
Neurons drug effects
Nicotinic Agonists pharmacology
Nicotinic Antagonists pharmacology
Organ Culture Techniques
Pedunculopontine Tegmental Nucleus drug effects
Rats
Rats, Sprague-Dawley
Receptors, Muscarinic drug effects
Receptors, Nicotinic drug effects
Sleep, REM physiology
Sodium Channel Blockers pharmacology
Synaptic Transmission drug effects
Synaptic Transmission physiology
Acetylcholine metabolism
Neurons metabolism
Pedunculopontine Tegmental Nucleus growth & development
Pedunculopontine Tegmental Nucleus metabolism
Receptors, Muscarinic metabolism
Receptors, Nicotinic metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-8993
- Volume :
- 1129
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Brain research
- Publication Type :
- Academic Journal
- Accession number :
- 17156760
- Full Text :
- https://doi.org/10.1016/j.brainres.2006.10.046