Affect the Parasympathetic Nervous System

N.A. Alkaloids, peimine." Affects the parasympathetic nervous system. 

Antipsychotic medications block acetylcholine receptors and thereby affect the parasympathetic nervous system. This leads to dry membranes (especially mouth and eyes), blurred vision (especially near vision), intestinal slowing (constipation), difficulty urinating, sedation, and sexual dysfunction. These symptoms may be very mild or, depending on the type of medication, quite severe and disabling. 

What is the role of cardiac reflexes in the therapeutic use and efficacy of drugs that affect the parasympathetic nervous system ... 

Drugs that affect the parasympathetic nervous system tend to produce a high degree of baroreceptor-mediated responses under normal usage. Thus, their responses are typically limited in duration, irrespective of drug half-life. This may not apply when the drug is used under life threatening conditions (e.g.. the use of atropine in the resuscitation of cardiac failure), because the baroreceptor reflex is set at normal levels of tension. 

DRUGS THAT AFFECT THE PARASYMPATHETIC NERVOUS SYSTEM... 

Drugs that Affect the Parasympathetic Nervous System... 

General types of physiological functions attributed to quaternary ammonium compounds are curare action, muscarinic—nicotinic action, and ganglia blocking action. The active substance of curare is a quaternary that can produce muscular paralysis without affecting the central nervous system or the heart. Muscarinic action is the stimulation of smooth-muscle tissue. Nicotinic action is primary transient stimulation and secondary persistent depression of sympathetic and parasympathetic ganglia. 

Nerve Agent is an agent which affects bodily functions by reacting with the enzyme acetylcholinesterase, permitting accumulation of acetylcholine and continual stimulation of the parasympathetic nervous system, as well as affecting other parts of the autonomic nervous system. 

Dmgs can affect cardiac contraction by stimulating or inhibiting the heart. Contractions are also influenced by the autonomic nervous system (ANS). The sympathetic nervous system increases heart rate and the parasympathetic nervous system decreases heart rate. (See Chapter 15.)... 

The sacrum forms a vital link between the spinal column and the ring-shaped pelvis and the lower extremities. Dysfunctions of the sacral-pelvic complex can affect normal function of the spinal column, gait, childbearing, pelvic viscera, and can be involved in a host of localized painful conditions. The lower fibers of the parasympathetic nervous system exit from the spinal canal through the sacral foramina along with motor and sensory nerves. Sacral dysfunctions can therefore be involved in widespread effects on tissues and organs iimervated by these nerves. 

To evaluate HRV, several measures have been proposed. These measures are roughly classifiable into time domain analysis [5], frequency domain analysis, and nonlinear and fractal analysis [5]. Time domain analysis includes tone-entropy method [6]. Nonlinear and fractal analysis include de-trended fluctuation analysis (DFA) [7]. Frequency domain analysis is based on estimation of the power spectrum of RRI series. Depending on the estimation method of power spectrum, frequency domain analysis is classified into FFT method [8], AR model method [9], maximum entropy method [10], and complex de-modulation method [11]. Akselrod et al. [3] investigated the relation between spectral component of HRV and ANS activity [12]. They classified spectral component of HRV into a high-frequency (HF) band of 0.14-0.4 Hz, a low-frequency (LF) band of 0.04-0.14 Hz, a very-low-frequency (VLF) band of 0.003-0.04 Hz, and a ultra-low-frequency (ULF) band under 0.003 Hz. They further show that LF and HF components are affected from both sympathetic and parasympathetic nervous system activity and the parasympathetic nervous system activity, respectively [12]. Furthermore, VLF and ULF components are affected by the thermoregulation system [13],... 

It is well established that increased sympathetic nerve activity is associated with chronic heart failure (CHF) (Porter et al. 1990 Singh 2000 Olshansky 2005 Brodde et al. 2006 Watson et al. 2006). The increase in sympathetic activity is a compensatory mechanism that provides inotropic support to the heart and peripheral vasoconstriction. However, it promotes disease progression and worsens prognosis (Watson et al. 2006). The autonomic nervous system (ANS) is a very complex, balanced system that influences the initiation, termination, and perpetuation of atrial fibrillation (AF), and the AF affects the ANS (Olshansky, 2005). At rest, sympathetic and parasympathetic outflows are related reciprocally heart failure patients had high sympathetic and low parasympathetic outflows, and healthy subjects had low sympathetic and high parasympathetic outflows (Porter et al. 1990). 

Previous studies have shown that accommodation mediated via ciliary smooth muscle activity also receives sympathetic innervation. Sympathetic nerves reach the ciliary muscle through the uveal blood vessels in close association with arteries and terminal arterioles. The distribution of the adrenergic fibers in the ciliary muscle appears to vary across species. In primates sympathetic nerve terminals, mainly 3 receptors, can generally be found in the anterior portion of the ciliary muscle. The accommodative amplitude significantly decreased in human subjects after instillation of phenylephrine (an a agonist) or hydroxyamphetamine (an a and (3 agonist). Such observations provide evidence that both sympathetic and parasympathetic divisions of the autonomic nervous system can affect accommodation but not equally. Furthermore, the nature of sympathetic innervation can be summarized as follows ... 

Anticholinesterase insecticides phosphorylate the active site of cholinesterase in all parts of the body. Inhibition of this enzyme leads to accumulation of acetylcholine at affected receptors and results in widespread toxicity. Acetylcholine is the neurohormone responsible for physiologic transmission of nerve impulses from preganglionic and postganglionic neurons of the cholinergic (parasympathetic) nervous system, preganglionic adrenergic (sympathetic) neurons, the neuromuscular junction in skeletal muscles, and multiple nerve endings in the central nervous system (Fig. 10-5). 

The acetylcholine is accumulated in the parasympathetic nerve endin that supply the smooth muscle action to the iris, ciliary body of the eye, tl bronchial tree, blood vessels, gastrointestinal tract, and urinary bladder. Tl secretory glands of the respiratory tract are similarly inhibited, as are the sympathetic nerve endings to the sweat glands. Voluntary muscles are paralyzed through accumulations of acetylcholine in the motor nerve endings. The central nervous system is likewise affected. 

HoAvever, Schweitzer and Wright (8) claim different results, and state that atropine decreases the inhibitory action of acetylcholine on the respiratory center. Gesell and Hansen (127) admit that atropine abolishes all respiratory modifications due to eserine or acetylcholine. However, Hey-mans and coworkers (128) observed that atropine, acting on the central nervous system, does not affect the direct or reflex excitability of the respiratory center or the parasympathetic cardio-inhibitory center. 

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