A-Epinephrine

Certain amino acids and their derivatives, although not found in proteins, nonetheless are biochemically important. A few of the more notable examples are shown in Figure 4.5. y-Aminobutyric acid, or GABA, is produced by the decarboxylation of glutamic acid and is a potent neurotransmitter. Histamine, which is synthesized by decarboxylation of histidine, and serotonin, which is derived from tryptophan, similarly function as neurotransmitters and regulators. /3-Alanine is found in nature in the peptides carnosine and anserine and is a component of pantothenic acid (a vitamin), which is a part of coenzyme A. Epinephrine (also known as adrenaline), derived from tyrosine, is an important hormone. Penicillamine is a constituent of the penicillin antibiotics. Ornithine, betaine, homocysteine, and homoserine are important metabolic intermediates. Citrulline is the immediate precursor of arginine. 

FIG. 17 Chemical structures of (a) epinephrine hydrochloride, (b) dopamine hydrochloride, (c) isoproterenol hydrochloride, (d) phenylephrine hydrochloride, (e) tolazoline hydrochloride, (f) oxyprenolol hydrochloride, (g) alprenolol hydrochloride, and (h) propranolol hydrochloride. 

Which of the following is the primary excitatory neurotransmitter in the brain a epinephrine... 

Lindner KH, Ahnefeld FW, Grunert A. Epinephrine versus norepinephrine in prehospital ventricular fibrillation. Am J Cardiol 1991 67 427 28. 

Myburgh JA, Upton RN, Grant C, Martinez A. Epinephrine, norepinephrine and dopamine infusions decrease propofol concentrations during continuous propofol infusion in an ovine model. Intensive Care Med (200 ) 27, 276-82. 

Mackie K, Lam A. Epinephrine-containii test dose during beta-blockade. J Clin Momt... 

Authons A Epinephrine (mg % ) Norepinephrine (mg % ) Total catecholamines (mg %) % Epine- % Norep-phrine inephrinc... 

Hoffer, A., Epinephrine derivatives as potential schizophrenic factors, J. Clin. Exp, Psychopath. 18, 27 (1957). 

---