Increased brain activation during verbal learning in obstructive sleep apnea.

This study examined the cerebral response to a verbal learning (VL) task in obstructive sleep apnea (OSA) patients. Twelve OSA patients and 12 controls were studied with functional magnetic resonance imaging (FMRI). As hypothesized, VL performance was similar for both groups, but OSA patients showed increased brain activation in several brain regions.

Barrett's esophagus.

Gastroesophageal reflux disease (GERD) is a condition commonly managed in the primary care setting. Patients with GERD may develop reflux esophagitis as the esophagus repeatedly is exposed to acidic gastric contents. Over time, untreated reflux esophagitis may lead to chronic complications such as esophageal stricture or the development of Barrett's esophagus.

Effects of sleep deprivation on sleepiness and increased REM sleep in rats selectively bred for cholinergic hyperactivity.

In this study we employed a modification of the multiple sleep latency test (MSLT) to determine whether rats of a strain with increased cholinergic activity were sleepier compared to randomly bred control rats. Seven rats each from the Flinders sensitive line (FSL, hypercholinergic) and Flinders resistant line (FRL, age-matched controls) were kept awake for 20 min and then allowed to sleep ad libitum for 20 min. The regimen of 20 min of wakefulness followed by 20 min of sleep was repeated 12 times during the day.

Cholinergic antagonists and REM sleep generation.

In this study we extended our observations on the role of M1 and M2 muscarinic receptors in mediating the cholinergic induction of REM sleep. Cats were chronically implanted with sleep recording electrodes and microinjections of Ringer's or muscarinic antagonists followed by the relatively specific M2 muscarinic agonist, cis-methyl-dioxolane (cisdioxo), were made into the medial pontine reticular formation (mPRF). The microinjection of Ringer's followed by cisdioxo significantly increased REM sleep percentage.

Microinjections of nicotine in the medial pontine reticular formation elicits REM sleep.

Microinfusion of non-specific cholinergic muscarinic-nicotinic agonists, such as carbachol, into the medial pontine reticular formation readily elicits REM sleep. It has generally been assumed that muscarinic receptors mediate the action of cholinergic agonists in triggering rapid eye movement (REM) sleep. Very little is known, however, about the role of nicotinic mechanisms in REM sleep generation.

Differential effects of cholinergic antagonists on REM sleep components.

We examined the effects of cholinergic receptor blockers on changes in rapid eye movement (REM) sleep components. M1 and M2 muscarinic receptor antagonists or atropine were microinfused before an M2 muscarinic receptor agonist, and the effects on individual REM sleep components were assessed. All drugs were microinjected into the same locus within the medial pontine reticular formation in cats, and sleep recordings were made for at least 3 hours postinjection.