Rapid eye movement (REM) sleep results in profound state-dependent alterations in heart rate. The present study describes a novel phenomenon of a primary deceleration in heart rate that is not preceded or followed by @entity551 and occurs primarily during @entity11755 . The goals were to characterize the primary decelerations and to provide insights on the underlying central and peripheral autonomic mechanisms. @entity468 were chronically implanted with electrodes to record electroencephalogram, pontogeniculooccipital wave activity in lateral geniculate nucleus, hippocampal theta rhythm, electromyogram, electrooculogram, respiration (diaphragm), and electrocardiogram. Arterial blood pressure was monitored from a carotid artery catheter. R-R interval fluctuations were continuously tracked using customized software. The muscarinic blocking agent glycopyrrolate (0.1 mg/kg i.v.) and the beta-adrenergic blocking agent @entity2165 (0.3 mg/kg i.v.) were administered in alternating sequence with a 90- to 120-min interval. @entity10445 immediately eliminated the decelerations during REM sleep. @entity2165 alone had no effect on their frequency. These findings suggest that a change in the centrally induced pattern of autonomic activity to the heart is responsible for the primary decelerations, namely, a bursting of cardiac vagal efferent fiber activity.

Primary vagally mediated decelerations in heart rate during tonic rapid eye movement sleep in XXXX .

@entity10445 :: ('MESH:D006024', 'Chemical') :: ['Glycopyrrolate'] @entity2165 :: ('MESH:D001262', 'Chemical') :: ['atenolol', 'Atenolol'] @entity11755 :: ('MESH:D020187', 'Disease') :: ['tonic REM sleep'] @entity468 :: ('9685', 'Species') :: ['Cats'] @entity551 :: ('MESH:D007022', 'Disease') :: ['increases in heart rate or arterial blood pressure']
@entity468 :: (9685,Species) :: ['cats']
