Metaraminol: A sympathomimetic agent that acts predominantly at alpha-1 adrenergic receptors. It has been used primarily as a vasoconstrictor in the treatment of HYPOTENSION.Methyltyrosines: A group of compounds that are methyl derivatives of the amino acid TYROSINE.Alphaprodine: An opioid analgesic chemically related to and with an action resembling that of MEPERIDINE, but more rapid in onset and of shorter duration. It has been used in obstetrics, as pre-operative medication, for minor surgical procedures, and for dental procedures. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1067)Polygeline: A 3.5 per cent colloidal solution containing urea-cross-linked polymerized peptides. It has a molecular weight of approximately 35,000 and is prepared from gelatin and electrolytes. The polymeric solution is used as a plasma expander.Priapism: A prolonged painful erection that may lasts hours and is not associated with sexual activity. It is seen in patients with SICKLE CELL ANEMIA, advanced malignancy, spinal trauma; and certain drug treatments.Ephedrine: A phenethylamine found in EPHEDRA SINICA. PSEUDOEPHEDRINE is an isomer. It is an alpha- and beta-adrenergic agonist that may also enhance release of norepinephrine. It has been used for asthma, heart failure, rhinitis, and urinary incontinence, and for its central nervous system stimulatory effects in the treatment of narcolepsy and depression. It has become less extensively used with the advent of more selective agonists.Normetanephrine: A methylated metabolite of norepinephrine that is excreted in the urine and found in certain tissues. It is a marker for tumors.Isonipecotic AcidsTyramine: An indirect sympathomimetic. Tyramine does not directly activate adrenergic receptors, but it can serve as a substrate for adrenergic uptake systems and monoamine oxidase so it prolongs the actions of adrenergic transmitters. It also provokes transmitter release from adrenergic terminals. Tyramine may be a neurotransmitter in some invertebrate nervous systems.Adrenergic Agents: Drugs that act on adrenergic receptors or affect the life cycle of adrenergic transmitters. Included here are adrenergic agonists and antagonists and agents that affect the synthesis, storage, uptake, metabolism, or release of adrenergic transmitters.