Sympathectomy chemical

Madden, K.S. et al., Sympathetic neural modulation of the immune system. I. Depression of T cell immunity in vivo and in vitro following chemical sympathectomy, Brain Behav. Immun., 3, 72, 1989. 

Bellinger, D.L. et al., Aging and sympathetic modulation of immune function in Fischer 344 rats Effects of chemical sympathectomy on primary antibody response, J. Neuroim-munol., in press, 2005. 

Kelley, S.P. et al., Chemical sympathectomy has no effect on the severity of murine AIDS Murine AIDS alone depletes norepinephrine levels in infected spleen, Brain Behav. Im-mun., 16, 118, 2002. 

Pharmacology Bretylium tosylate inhibits norepinephrine release by depressing adrenergic nerve terminal excitability, inducing a chemical sympathectomy-like state. Bretylium blocks the release of norepinephrine in response to neuron stimulation. Peripheral adrenergic blockade causes orthostatic hypotension but has less effect on supine blood pressure. It has a positive inotropic effect on the myocardium. Pharmacokinetics Peak plasma concentration and peak hypotensive effects are seen within 1 hour of IM administration. However, suppression of premature ventricular beats is not maximal until 6 to 9 hours after dosing, when mean plasma concentration declines to less than 50% of peak level. Antifibrillatory effects occur within minutes of an IV injection. Suppression of ventricular tachycardia and other ventricular arrhythmias develops more slowly, usually 20 minutes to 2 hours after parenteral administration. 

Thoenen H, Tranzer JP (1968) Chemical sympathectomy by selective destruction of adrenergic nerve endings with 6-hydroxydopamine. Naunyn-Schmied. Arch Pharmacol 261. 211-288. 

Patients taking certain systemic medications are also more sensitive to the pressor effects of phenylephrine. In individuals taking atropine, the pressor effect of phenylephrine is augmented, and tachycardia can occur. Tricyclic antidepressants and monoamine oxidase (MAO) inhibitors also potentiate the cardiovascular effects of topical phenylephrine. The concomitant use of phenylephrine is contraindicated with these agents, even up to 21 days after cessation of MAO inhibitor therapy. Similarly, patients taking reserpine, guanethidine, or methyldopa are at increased risk for adverse pressor effects from topical phenylephrine because of denervation hypersensitivity accompanying the chemical sympathectomy. 

Contraindications to the topical use of hydroxyamphetamine for routine mydriasis are similar to those to phenylephrine. Because of its tachyphylaxis and ineffectiveness in postganglionic denervation, however, hydroxyamphetamine may be a safer mydriatic for use in patients with insulin-dependent diabetes, idiopathic orthostatic hypotension, or chemical sympathectomy produced by therapy with systemic guanethidine, reserpine, or methyl-dopa. Thus hydroxyamphetamine seems to be less strongly contraindicated than phenylephrine for certain high-risk patients. 

A 44-year-old woman developed claudication and rest pain after gross overuse of ergotamine 100 mg suppositories (up to 6 times a day) for chronic headaches over a period of several years (14). Angiography showed occlusion of both femoral arteries. Intraarterial prostaglandin E (presumably Ei) followed by chemical sympathectomy normalized the circulation in both the legs. 

Mienoxybenzamine. The action of phenoxybenza-minc (Dibcn/.ylinc) has been described as representing a "chemical. sympathectomy" because of its selective blockade of the excitatory responses of smooth muscle and of the heart muscle. Although phenoxybenzamine is capable of... 

There are descriptions in the literature of the use of phenol in chemical sympathectomies in the treatment of palmar hyperhidrosis, Raynaud s syndrome and obliterative arteriopathy. 

Several studies have demonstrated that chemical sympathectomy increases the concentration of NGF 2 to 5-fold in effector tissues such as the submandibular iris and heart (Ebendal et al., 1980 Korsching and Thoenen, 1985 Whittemore et al.,... 

Hydroxydopamine produces in animal experiments a kind of chemical sympathectomy by causing degenerative destruction of adrenergic nerves [136,... 

Rats submitted to chemical sympathectomy (drug-induced depletion of peripheral catecholamine stores combined with surgical removal of the adrenal medulla) have normal FFA and glucose levels at controlled body temperature, but when exposed to a cold environment ( 4°C) they are unable to mobilize additional FFA and their body temperature declines rather rapidly. Similar results are obtained by ganglionic blockade following the surgical removal of the adrenal medulla. 

Guanethidine, an adrenergic neuroneblocking agent, is useful in cases of glaucoma, chemical sympathectomy, ptosis and lid retraction. The reduction in lOP is relatively small. Tissues treated with guanethidine become sensitized to sympathomimetic-acting... 

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