Effect of rapid eye movement sleep deprivation on allergen-induced airway responses in a rat model of asthma.

Background: Nocturnal airway narrowing is a common characteristic of asthma that remains poorly understood. Sleep itself or rapid eye movement (REM) sleep has been suspected to play a role in the etiology of nocturnal asthma; however, only inconsistent findings have so far been produced. The purpose of this study was to examine the effect of sleep deprivation, particularly REM sleep, using the classical platform (flowerpot) method on asthmatic responses in a rat model of asthma, in a situation of immobilization stress.

Changes in blood pressure and muscle sympathetic nerve activity during water drinking in humans.

To investigate the possible involvement of the sympathetic nervous system in pressor response during water drinking, muscle sympathetic nerve activity (MSNA), blood pressure (BP), and heart rate (HR) were continuously measured in healthy young volunteers throughout the experiments of a 5-min control, 2 min of drinking 500 ml water, and a 28-min recovery. To avoid the effects of water passing through the oropharyngeal and esophageal regions and/or effects of swallowing, an equal amount of water was directly infused to the stomach through a stomach tube for 2 min. Water drinking caused a transient increase in mean arterial pressure (MAP) and HR immediately after drinking (DeltaMAP, 12.

Whole body heating reduces the baroreflex response of sympathetic nerve activity during Valsalva straining.

The present experiment was carried out to examine the possible effects of whole body heating on the baroreflex control of muscle sympathetic nerve activity (MSNA) and heart rate (HR). Nine healthy male volunteers underwent the Valsalva maneuver during exposure to heat stress using a hot water-perfused suit. To exclude an effect from the unloading of the cardiopulmonary baroreceptors during hyperthermia, the central hypovolemia was counterbalanced by head-down tilt (HDT) at 8 degrees.

Fasting stress exacerbates classical conditioned histamine release in guinea pigs.

To clarify the contribution of stress to classical conditioning-associated asthmatic responses, the effect of fasting stress on conditioned histamine release was investigated in a guinea pig model of asthma. The animals were randomly divided into 2 groups for Experiment 1 and 2, and received a conditioning procedure in which ovalbumin (OA) as an unconditioned stimulus (US) and dimethylsulfide (DMS, sulfur smelling) as a conditioned stimulus (CS) were simultaneously inhaled after fasting for 16 h. Then, one group was given food as a reward for respiratory distress, and the other group was denied it for more than 3 h, while being placed in front of the feeding group.

Effect of isolation on classical conditioned histamine release in guinea pigs.

To investigate the effect of abrupt or non-abrupt isolation stress on the classical conditioned histamine release, socially isolated or paired guinea pigs underwent conditioning procedures in which ovalbumin (OA) as an unconditioned stimulus (US) and dimethylsulfide (sulfur smelling) as a conditioned stimulus (CS) were simultaneously inhaled, and the plasma histamine levels after the exposure to the CS in a state of isolation or pairing were measured. The plasma histamine levels significantly increased from baseline in response to the CS (P < 0.05), except in the animals which were abruptly isolated during the exposure to the CS.

Selective suppression of hippocampal region hyperexcitability related to seizure susceptibility in epileptic El mice by the GABA-transporter inhibitor tiagabine.

High seizure susceptibility in El mice is associated with disinhibition in the dentate gyrus (DG) and paired-pulse facilitation in the CA3 area in hippocampal slices [Brain Res. 745 (1997) 165; Brain Res. 779 (1998) 324].

Cardiovascular responses to lower body negative pressure in the elderly: role of reduced leg compliance.

Background: It is warranted to test the hypothesis that the orthostatic tolerance does not diminish in the aging process per se in healthy individuals.

Objective: The purpose of the present study was to examine the effects of aging on cardiovascular response and baroreflex sensitivity during lower body negative pressure (LBNP) with a special reference to leg compliance.

Methods: Fifteen healthy old male subjects [mean age 68.

Sympathetic nervous and hemodynamic responses to lower body negative pressure in hyperbaria in men.

The present study was designed to test the hypothesis that sympathetic nerve activity is attenuated in a hyperbaric environment. Response of muscle sympathetic nerve activity (MSNA) to central circulatory hypovolemic stress, lower body negative pressure (LBNP), was measured in nine men at normal and at 3 atm pressures. The stress consisted of 4 min each of control and LBNP at -20 and -40 mmHg.