Adrenergic agents, active

This peripheral activity may be a rational basis for the use of systemic local anaesthetics in neuropathic states since ectopic activity in damaged nerves has been shown to be highly sensitive to systemic sodium channel blockers. This too is probably part of the basis for the analgesic effects of established effective anti-convulsants that block sodium channels such as carbamazepine, although central actions are important and may even predominate. The precise actions of excitability blockers therefore remains hazy as does any clear basis for the effectiveness of antidepressants and other adrenergic agents in the treatment of neuropathic pain as both central and peripheral actions, including sympathetic effects are possible. 

Norepinephrine is a potent a-adrenergic agent with less pronounced P-adrenergic activity. Doses of 0.01 to 3 mcg/kg per minute can reliably increase blood pressure with small changes in heart rate or cardiac index. Norepinephrine is a more potent agent than dopamine in refractory septic shock.24,27-28... 

Dopamine is a a- and P-adrenergic agent with dopaminergic activity Low doses of dopamine (1 to 5 mcg/kg per minute) maintain renal perfusion, higher doses (greater than 5 mcg/kg per minute) exhibit a- and P-adrenergic activity and are frequently utilized to support blood pressure and to improve cardiac function. Low doses of dopamine should not be used for renal protection as part of the treatment of severe sepsis.24,27-28... 

Drugs with a-adrenergic blocking activity are peripheral coronary-dilating agents that only differ in specificity with aj-adrenergic receptors. Prazozin and tetrazin are selective aj-adrenoblockers that are used in therapeutic doses to lower arterial pressure. 

Nonallergic bronchospasm (eg, chronic bronchitis, emphysema) n general, these patients should not receive propafenone or other agents with beta-adrenergic blocking activity. 

Pharmacology Carvedilol, an antihypertensive agent, is a racemic mixture in which nonselective -adrenoreceptor blocking activity is present in the S(-) enantiomer and -adrenergic blocking activity is present in both R(+) and S(-) enantiomers at equal potency. Carvedilol has no intrinsic sympathomimetic activity. 

Dopamine itself has long been used as an inotropic agent in acute treatment of congestive heart failure. Both that compound and a number of its analogues have a positive action on contractility as a consequence of their adrenergic agonist activity. 

In rat pars intermedia cells, the rate of secretion of the proopiomelanocortin-derived peptides (a-MSH being the major secretory product) (3, 85) was so far known to result from a balance between the stimulatory effect of B-adrenergic agents and the inhibitory influence of dopaminergic substances (14, 41, 86-89). The present data clearly demonstrate that in addition to B-adrenergic agents, a second substance, namely CRF, could well be involved as physiological stimulator of the activity of pars intermedia cells. 

Patients with Down syndrome are hypersensitive to topically applied anticholinergic agents. The pupils often dilate widely in response to tropicamide, reflecting an imbalance between cholinergic and adrenergic autonomic activity in the iris. Cyclopentolate, scopolamine, homatropine, and atropine should therefore be avoided in these patients if at all possible. 

Dailey MO, Schreurs J, Schulman H (1988) Hormone receptors on cloned T lymphocytes. Increased responsiveness to histamine, prostaglandins, and beta-adrenergic agents as a late stage event in T cell activation. J Immunol 140 2931-2936. 

Dunn III, W.J., Wold, S. and Martin, Y.C (1978). Structure-Activity Study of p-Adrenergic Agents Using the SIMCA Method of Pattern Recognition. J.Med.Chem., 21,922-930. 

Peterson DA, Gerrard JM. Reduction of a disulfide bond by p-adrenergic agonists evidence in support of a general reductive activation hypothesis for the mechanism of action of adrenergic agents. Med Hypotheses 1987 22 45-49. 

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