Norepinephrine ephedrine effects

The modern usage of P2" go Asts for the treatment of asthma dates to 1903 when the effect of injected epinephrine [51-43-4] (adrenaline) C2H23NO2, (1 R = CH3) was investigated (see Epinephrine and norepinephrine) (33). As in some other modem treatments, eg, xanthines and anticholinergics, the roots of P2" go Ast therapy for asthma can be found in historical records which document the use of herbal extracts containing ephedrine [299-42-3] C qH NO, (2) as bronchodilators. Epinephrine and ephedrine are stmcturaHy related to the catecholamine norepinephrine [51-41-2] CgH NO, (1, R = H), a neurotransmitter of the adrenergic nervous system (see Neuroregulators). 

Interactions with caffeine and aspirin can increase the effects of ephedrine. Norepinephrine works in part by increasing the levels of cyclic aminomethyl propanol (AMP) in cells. Caffeine inhibits the enzyme that breaks down cyclic AMP. Together, ephedrine makes more cyclic AMP, and caffeine prevents it from breaking down. Aspirin inhibits the receptors that turn off release of norepinephrine. 

As drugs of mixed action, amphetamines activate adrenergic receptors and simultaneously release endogenic catecholamines (norepinephrine and dopamine) from neurons of the brain and periphery. Sympathomimetic effects on the periphery are very similar to those of ephedrine. Amphetamine elevates systolic and diastolic blood pressure and has weakly expressed, broncholytic action. These effects are more prolonged, yet less expressed, than with epinephrine. The distinctive feature of amphetamines is their psychostimulatory activity. Larger doses can cause hallucinations and mental conditions similar to paranoid schizophrenia. As a sympathomimetic, amphetamine is sometimes used for uterine inertia. Synonyms of amphetamine are phenamine and benzedrine. 

Ephedrine is a naturally occurring alkaloid that can cross the blood-brain barrier and thus exert a strong CNS-stim-ulating effect in addition to its peripheral actions. The latter effects are primarily due to its indirect actions and depend largely on the release of norepinephrine. However, ephedrine may cause some direct receptor stimulation, particularly in its bronchodilating effects. Because it resists metabolism by both COMT and MAO, its duration of action is longer than that of norepinephrine. As is the case with aU indirectly acting adrenomimetic amines,... 

Amphetamine is an indirectly acting adrenomimetic amine that depends for its action on the release of norepinephrine from noradrenergic nerves. Its pharmacological effects are similar to those of ephedrine however, its CNS stimulant activity is somewhat greater. Both systolic and diastolic blood pressures are increased by oral dosing with amphetamine. The heart rate is frequently slowed reflexively. Cardiac output may remain unchanged in the low- and moderate-dose range. 

Norephedrine and ephedrine mimic and stimulate the release of the adrenal hormones norepinephrine and epinephrine. Norephinephrine raises heart rate and epinephrine stimulates carbohydrate metabolism resulting in an increased metabolic rate, fatty acids release from lipocytes (fat cells), and a protein sparing effect. Caffeine simply prolongs the effect. 

Correct answer = D. Reserpine blocks the uptake of norepinephrine into intracellular storage vesicles, resulting in depletion of norepinephrine and gradual decline in blood pressure. Phenylephrine is a pure vasoconstrictor and raises systolic and diastolic blood pressures. Dopamine raises systolic and diastolic blood pressures by stimulating the heart and (at high doses) causing vasoconstriction. Ephedrine raises systolic and diastolic blood pressures by vasoconstriction and cardiac stimulation. Norepinephrine has a pressor effect. 

Figure 2.10 Amphetamine 30, methamphetamine 31, and methylenedioxymethamphetamine 32 (MDMA, ecstasy, XTC) are lipophilic compounds with good oral bioavailability they easily cross the blood-brain barrier to exert central nervous system effects. Dopamine 33, norepinephrine (noradrenalin) 34, and epinephrine (adrenaline) 35 are polar phenethylamines they have poor oral efficacy and do not pass the blood-brain barrier, producing only peripheral effects after intravenous application. Ephedrine 36 has intermediate lipophilicity besides its peripheral effects it also acts as a central stimulant. Although L-dopa 37 is even more polar than dopamine 33, it is orally active and crosses the blood-brain barrier by active transport mediated by the amino acid transporter.

Fundamentally, there are only two ways to treat obesity reduce El and increase EE. Thermogenesis and fat oxidation are to a large extent under the control of the sympathetic nervous system and its neurotransmitter norepinephrine after a rational approach for obesity management. In this context, there has been much interest in the potential thermogenic effects of many compounds extracted from plants, namely, caffeine from coffee and tea, ephedrine from ephedra, and capsaicin from pungent spices, largely because of their potential to modulate catecholamine release and activity. ... 

After 5 to 10 days of use furazolidone has MAO-inhibitory activity about equivalent to that of the non-selective MAOIs. The concurrent use of furazolidone with indirectly-acting sympathomimetic amines (amfetamines, phenylpropanolamine, ephedrine, etc.) or with tyramine-rich foods and drinks may be expected to result in a potentially serious rise in blood pressure. However, direct evidence of accidental adverse reactions of this kind does not seem to have been reported. The pressor effects of noradrenaline (norepinephrine) are unchanged by furazolidone. 

Some products containing ephedrine alkaloids are well-known dietary supplements. These alkaloids, namely, epinephrine and norepinephrine, naturally occur in low concentration in the human body. They have sympathomimetic effects and cause weight loss and enhanced athletic performance. According to new studies, ephedrine causes weight loss in lean but not in... 

Another common activity for a substituted )8-phenylethylamine is to accumulate in the presynaptic terminal and push the local stores of norepinephrine out into the synaptic gap. If this is done rapidly, the action must necessarily be of limited duration, as the stores eventually become depleted. Ephedrine 12.12) acts principally in this way (Schumann, 1961), and provides an excellent morning treatment for hay-fever, but its centrally stimulant effect causes disturbance of sleep if it is taken later in the day. The next morning, when norepinephrine stores have built up again in the adrenergic terminals, the patient can derive benefit from another dose. (Ephedrine, unlike norepinephrine, is not destroyed in the stomach and may be given orally.) Amphetamine 9.44) has this combination of peripheral and central actions but with the latter preponderating. Tyramine, on the other hand, has a purely peripheral action. 

Comparing the two actions described in the last two paragraphs (prevention of re-uptake of norepinephrine by presynaptic terminal, and enforced release of norepinephrine from this terminal), it is notable that, although many substances like metaraminol, tyramine, and ephedrine show both effects, they exercise these properties quite independently. In other words, when put into ranking order for one effect, they are not in order for the other (Burgen and Iversen, 1965). However, both classes of drug give the patient a temporary overdose of his own norepinephrine (Burn and Rand, 1958). 

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