Sympathetic nervous

Nitrous oxide produces respiratory depression (38,39). It has been shown to produce a direct myocardial depressant effect in dogs (40) and in humans breathing a 40% N2O/60% oxygen mixture (41) however, this may be offset by the activation of the sympathetic nervous system (42). The combination of nitrous oxide and opioids can produce decreases in myocardial contractiHty, heart rate, and blood pressure (43). 

Enhanced automaticity occurs in hypoxia, hypokalemia, hypercarbia, excessive sympathetic nervous system stimulation, or high concentrations of catecholamines. These conditions may lead to arrhythmias. Decreased automaticity may also lead to production of arrhythmias by enhancing ectopic activity in latent pacemakers (ectopic foci) or by altering conductivity and refractoriness in conduction pathways of myocardium. 

Cusparia bark is used in medicine as a simple bitter. Raymond-Hamet states that cusparine has sympathicosthenic properties, that is it increases the sensitivity of the sympathetic nervous system to stimulation, e.g., by adrenaline. 

Sympathetic nervous system. That portion of the autonomic nervous system that utilizes norepinephrine as a neurotransmitter at its neuroeffector junctions. 

Sympathomimetic. A drug that produces effects similar to stimulating the sympathetic nervous system, that is, increased blood pressure, dilated bronchi, and mydriasis. 

The phenyl ethanol amine derivatives epinephrine (U and norepinephrine ( ) are intimately associated with the sympathetic nervous system. These two neurotransmitter hor-... 

Acetylcholine (Ach) is an ester of acetic acid and choline with the chemical formula CH3COOCH2CH2N+ (CH3)3. ACh functions as a chemical transmitter in both the peripheral nervous system (PNS) and central nervous system (CNS) in a wide range of organisms, humans included. Neurotransmitter involved in behavioral state control, postural tone, cognition and memory, and autonomous parasympathetic (and preganglionic sympathetic) nervous system. 

The part of the vertebrate nervous system that regulates involuntary action, such as the intestines, heart and glands it is divided into the sympathetic nervous system and the parasympathetic nervous system. 

The regulation of the total peripheral resistance also involves the complex interactions of several mechanisms. These include baroreflexes and sympathetic nervous system activity response to neurohumoral substances and endothelial factors myogenic adjustments at the cellular level, some mediated by ion channels and events at the cellular membrane and intercellular events mediated by receptors and mechanisms for signal transduction. As examples of some of these mechanisms, there are two major neural reflex arcs (Fig. 1). Baroreflexes are derived from high-pressure barorecep-tors in the aortic arch and carotid sinus and low-pressure cardiopulmonary baroreceptors in ventricles and atria. These receptors respond to stretch (high pressure) or... 

NET (SLC6A2) Noradre-naline, dopamine 1 CNS noradrenergic neurons (emanate from locus coeruleus and lateral tegmental area), sympathetic nervous system Clearance of interstitial neuro-transmitter, reuptake into neurons... 

Due to its expression in the sympathetic nervous system NET activity is important in limiting the effects of... 

Sympatholytic drugs are a group of drugs, which decrease the activity of the sympathetic nervous system, mainly by blocking the action of adrenaline and noradrenaline at adrenoceptors. 

N euro transmitters are chemical substances called neurohormones. These are released at Hie nerve ending that facilitate the transmission of nerve impulses. The two neurohormones (neurotransmitters) of the sympathetic nervous system are epinephrine and norepinephrine Epinephrine is secreted by the adrenal medulla Norepinephrine is secreted mainly at nerve ending of sympathetic (also called adrenergic) nerve fibers (Pig. 22-2). 

Adrenergic dru mimic the activity of the sympathetic nervous system. These dragp also are called sympathomimetic druc s. Epinephrine and norepinephrine are neurohormones produced naturally by the body. Synthetic preparations of these two neurohormones,... 

One group of antiadreneigic drugs inhibits the release of norepinephrine (a neurohormone of the sympathetic nervous system, see Chap. 22) from certain adrenergic... 

Sympathomimetics (drugs that mimic the sympathetic nervous system) are used primarily to treat reversible airway obstruction caused by bronchospasm associated with acute and chronic bronchial asthma, exercise-induced bronchospasm, bronchitis, emphysema, bronchiectasis (abnormal condition of the bronchial tree), or other obstructive pulmonary diseases. 

Increased secretion of the neurohormones by the sympathetic nervous system... 

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