Key Terms
“a neurotransmitter in the catecholamine family that mediates chemical communication in the sympathetic nervous system, a branch of the autonomic nervous system. Like other neurotransmitters, it is released at synaptic nerve endings to transmit the signal from a nerve cell to other cells. Norepinephrine is almost identical in structure to epinephrine , which is released into the bloodstream from the adrenal medulla under sympathetic activation. The sympathetic nervous system functions in response to short-term stress; hence norepinephrine and epinephrine increase the heart rate as well as blood pressure. Other actions of norepinephrine include increased glycogenolysis (the conversion of glycogen to glucose ) in the liver, increased lipolysis (the conversion of fats to fatty acids; see fats and oils ) in adipose (fat) tissue, and relaxation of bronchial smooth.”
Locus Coeruleus: (Etymology: L, locus, place, caeruleus, sky-blue)
“. . . a deeply pigmented group of several thousand neurons in the floor of the fourth ventricle. It is part of a major norepinephrine pathway of the central nervous system.”
Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
Cholinergic System:
“A system of nerve cells that uses acetylcholine in transmitting nerve impulses. The cholinergic system is a neurotransmitter system involved in the regulation of memory and learning. It is this system that degenerates in Alzheimer's disease.”
“A venerable drug that is a naturally occurring member of a large chemical class of compounds called alkaloids. Scopolamine was first introduced into medical usage in 1902. The name comes from that of the 18th-century Italian naturalist Giovanni Scopoli.Scopolamine is, together with atropine, a component of belladonna which comes from a plant called "deadly nightshade," once used as a means of poisoning. When scopolamine is given in lower (non-poisonous) doses, it causes drowsiness and amnesia and sometimes a sense of euphoria (a "high"). Scopolamine together with morphine provided childbirth without pain (or without the memory of pain), once a much sought-after objective. Known as twilight sleep, this combination of drugs could cause serious problems. It completely removed the mother from the birth experience and it gravely depressed the baby's central nervous system. This sometimes made for a drowsy depressed baby with depressed breathing capacity. Twilight sleep therefore has fallen entirely out of favor and is now a chapter in the history of obstetrics.”
“An important neurotransmitter (messenger) in the brain. Dopamine is classified as a catecholamine (a class of molecules that serve as neurotransmitters and hormones). It is a monoamine (a compound containing nitrogen formed from ammonia by replacement of one or more of the hydrogen atoms by hydrocarbon radicals). Dopamine is a precursor (forerunner) of adrenaline and a closely related molecule, noradrenaline. Dopamine is formed by the decarboxylation (removal of a carboxyl group) from dopa. Dopa is used in the treatment of Parkinson disease. Parkinson disease is believed to be related to low levels of dopamine in certain parts of the brain. When dopa is taken by mouth, it crosses through the blood-brain barrier. Once it has crossed from the bloodstream into the brain, it is converted to dopamine. The resulting increase in dopamine concentrations in the brain is thought to improve nerve conduction and to assist in lessening the movement disorders in Parkinson disease. In 1970 the FDA (Food and Drug Administration) approved dopa in the form of L-Dopa, or levodopa, for use in the US. The drug revolutionized the treatment of Parkinson disease.”
“Methylphenidate is a central nervous system stimulant. It affects chemicals in the brain and nerves that contribute to hyperactivity and impulse control. Methylphenidate is used to treat attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD). It is also used to treat uncontrollable periods of daytime sleep (narcolepsy).”