Search results for "Sympathetic"
showing 10 items of 219 documents
Nicotine receptors do not modulate the 3H-noradrenaline release from the isolated rat heart evoked by sympathetic nerve stimulation.
1982
Isolated rat hearts with the right sympathetic nerves attached were perfused at a constant flow rate of 7 ml/min with Tyrode's solution. (-)-3H-Noradrenaline (final concentration 10–13.9 nM) was infused for 10 min to label the noradrenaline stores. After wash-out the sympathetic nerves were stimulated electrically (3 Hz, 180 impulses, 1 ms, 20–30 mA) three times (S1–S3) at intervals of 15 min. 3H-Noradrenaline and its metabolites were determined by liquid scintillation counting according to Graefe et al. (1973). Both, nicotine 50 μM and p-aminophenethyltrimethylammonium (PAPETA) 30 μM, enhanced the 3H-noradrenaline overflow in the absence of nerve stimulation. The effect of PAPETA was bipha…
Increased muscle sympathetic nerve activity and impaired baroreflex control in isolated REM-sleep behavior disorder.
2021
Changes in baroreflex sensitivity have been reported in patients with idiopathic Parkinson's disease (PD). We sought to investigate the hypothesis that patients with isolated rapid eye movement (REM)-sleep behavior disorder (iRBD), known to be a prodromal stage for PD, will show abnormalities in baroreflex control.Ten iRBD patients were compared to 10 sex- and age-matched healthy controls. Their cardiovascular parameters and muscle sympathetic nerve activity (MSNA) were evaluated at rest and during baroreflex stimulation.MSNA at rest was higher in iRBD patients (burst frequency [BF]: 44 ± 3 bursts/min; burst incidence [BI]: 60 ± 8 bursts/100 heartbeats) as compared to the controls (BF: 29 ±…
Gastric acid secretory responses induced by peptone are mediated by capsaicin-sensitive sensory afferent neurons
1992
The involvement of capsaicin-sensitive afferent neurons in modulating acid-secretory responses to peptone, a product of protein digestion, has been investigated in the continuously perfused stomach of the urethan-anesthetized rat. Systemic neonatal pretreatment with capsaicin, which destroys primary afferent neurons, does not modify basal levels of acid secretion. Acid responses to intragastric perfusion with isotonic (0.5, 1, and 2.4%) or hypertonic (10 and 20%) solutions of peptone were reduced in capsaicin-treated rats. Intragastric perfusion with hypertonic mannitol (18%) did not stimulate secretion of acid. Systemic capsaicin pretreatment did not modify acid responses to intraperitone…
The effect of physostigmine on the vagally induced muscarinic inhibition of noradrenaline release from the isolated perfused rabbit atria.
1982
1. Presynaptic cholinergic-adrenergic interactions were studied on isolated perfused rabbit atria with the extrinsic right vagus and sympathetic innervation intact. The transmitter stores were labelled with 14C-choline and 3H-noradrenaline. The radioactive compounds were separated on columns and determined by scintillation spectrometry. The stimulation-evoked overflow of both transmitters was calcium-dependent and abolished by tetrodotoxin. 2. Methacholine caused a concentration-dependent decrease of atrial tension development and 3H-noradrenaline overflow evoked by 3 Hz sympathetic stimulation. Vagus nerve stimulation (1–20Hz), although nearly abolishing tension development at 20Hz, decrea…
The inhibition by dopamine of cholinergic transmission in the isolated guinea-pig ileum. Mediation through alpha-adrenoceptors.
1982
1. Segments of the guinea-pig ileum were incubated in Tyrode's solution containing 3 μM propranolol. Dopamine, like noradrenaline and clonidine, inhibited the twitch response to field stimulation. The inhibitory action of dopamine remained unchanged in the presence of the dopamine uptake inhibitor nomifensine (1 μM). Tissue from reserpine-pretreated amimals was insensitive to tyramine but the response to dopamine was not affected. It is, therefore, assumed that the effect of dopamine is due to a direct receptor stimulation and not to the release of noradrenaline. 2. The inhibitory action of dopamine was not antagonized by the dopamine receptor antagonists cis-flupenthixol, pimozide or dompe…
Electrophysiological characterization of the pineal gland of golden hamsters.
1987
In one of the most-widely used species in pineal gland research, the strongly photoperiodic golden hamster, Mesocricetus auratus, no electrophysiological data on pinealocytes are currently available. To fill this gap, in the present study 185 spontaneously active pinealocytes from male golden hamsters were recorded extracellularly, both during day- and night-time (light: dark cycle 12 ∶ 12, lights on at 07.00 h). As in other species, pinealocytes exhibited action potentials of 1–2 ms duration. An irregular firing pattern was observed in 95% of the pinealocytes, the remainder fired more regularly or showed a phasic discharge pattern. The firing frequencies ranged from 0.2 to 25 Hz and showed…
Principal neurons projecting to the pineal gland in close association with small intensely fluorescent cells in the superior cervical ganglion of rats
1988
The localization in the superior cervical ganglia (SCG) of small, intensely fluorescent (SIF) cells and of principal nerve (PN) cells innervating the pineal gland was examined in adult male Sprague-Dawley rats. PN cells were demonstrated by means of the retrograde neuron-tracing method using the fluorescent tracer Fluoro-Gold (FG) injected into the pineal gland. SIF cells were visualized by the formaldehyde-induced fluorescence method. Twenty-nine percent of the FG-labeled PN cells were found closely associated with SIF cells. In the rostral half of the ganglion, 43% of the SIF cells were situated in juxtaposition to one or several labeled neurons. The possible influence of SIF cells on the…
Effects of alterations in sympathetic nervous activity on the severity of reperfusion-induced arrhythmias in anaesthetised rats.
1987
The effects of a number of interventions influencing sympathetic nervous activity on the severity of coronary artery reperfusion-induced arrhythmias in anaesthetised rats have been examined. Noradrenaline (0.1 microgram kg-1 min-1) reduced the mortality that usually occurred as a consequence of ventricular fibrillation. Isoprenaline (5 micrograms kg-1) did not significantly affect the severity of reperfusion-induced arrhythmias, although arrhythmias occurring during the 5-min period of ischaemia were exacerbated. The alpha-adrenoceptor antagonist nicergoline (0.25 and 0.5 mg kg-1 min-1) markedly suppressed both the ventricular tachycardia and fibrillation occurring upon release of the occlu…
Pavlovian conditioning of corticotropin-releasing factor-induced increase of blood pressure and corticosterone secretion in the rat
1992
Corticotropin-releasing factor (CRF) is clearly involved in the central regulation of the pituitary-adrenal axis and, moreover, of autonomic nervous system functions. Enhanced sympathetic activity with subsequent increases in blood pressure and heart rate and attenuation of the baroreceptor reflex results from the intracerebroventricular (i.c.v.) administration of CRF. Additionally, the peptide has a variety of potent effects on behavioural responses in animals similar to those observed after an experimentally evoked stress. It was therefore of obvious interest to examine whether CRF is a possible mediator of the learning processes associated with physiological stress reaction patterns. Thi…
Cardiac sympathetic activation and parasympathetic withdrawal during psychosocial stress exposure in 6‐month‐old infants
2020
Infant autonomic reactivity to stress is a potential predictor of later life health complications, but research has not sufficiently examined sympathetic activity, controlled for effects of physical activity and respiration, or studied associations among autonomic adjustments, cardiac activity, and affect in infants. We studied 278 infants during the repeated Still-Face Paradigm, a standardized stressor, while monitoring cardiac activity (ECG) and respiratory pattern (respiratory inductance plethysmography). Video ratings of physical activity and affect were also performed. Respiratory sinus arrhythmia (RSA) and T-wave amplitude (TWA) served as noninvasive indicators of cardiac parasympathe…