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CNS Drugs is a one-stop shop for all
important information about the drug
treatment of psychiatric and
neurological disorders. The journal
takes a bench to bedside approach,
covering topics from basic pharmacology
and disease pathology to drugs in
development and guidelines for clinical
practice.
Introduction
The central nervous system directs the
functions of all tissues of the body.
The peripheral nervous system receives
thousands of sensory inputs and
transmits them to the brain via the
spinal cord. The brain processes this
incoming information and discards 99% as
unimportant. After sensory information
has been evaluated, selected areas of
the central nervous system initiate
nerve impulses to organs or tissue to
make an appropriate response.
Chemical influences are capable of
producing a myriad of effects on the
activity and function of the central
nervous system. Since our knowledge of
different regions of brain function and
the neurotransmitters in the brain is
limited, the explanations for the
mechanisms of drug action may be vague.
The known neurotransmitters are:
acetylcholine which is involved with
memory and learning; norepinephrine
which is involved with mania-depression
and emotions; and serotonin which is
involved with biological rhythms, sleep,
emotion, and pain.
Central Nervous System Stimulants:
Stimulants are drugs that exert their
action through excitation of the central
nervous system. Psychic stimulants
include caffeine, cocaine, and various
amphetamines. These drugs are used to
enhance mental alertness and reduce
drowsiness and fatigue. However,
increasing the dosage of caffeine above
200 mg (about 2 cups of coffee) does not
increase mental performance but may
increase nervousness, irritability,
tremors, and headache. Heavy coffee
drinkers become psychically dependent
upon caffeine. If caffeine is withheld,
a person may experience mild withdrawal
symptoms characterized by irritability,
nervousness, and headache.
Amphetamines:
The stimulation caused by amphetamines
is caused by excessive release of
norepinephrine from storage sites in the
peripheral nervous system. It is not
known whether the same action occurs in
the central nervous system. Two other
theories for their action are that they
are degraded slower than norepinephrine
or that they could act on serotonin
receptor sites.
Therapeutic doses of amphetamine elevate
mood, reduce feelings of fatigue and
hunger, facilitate powers of
concentration, and increase the desire
and capacity to carry out work. They
induce exhilarating feelings of power,
strength, energy, self-assertion, focus
and enhanced motivation. The need to
sleep or eat is diminished.
Levoamphetamine (Benzedrine),
dextroamphetamine (Dexedrine), and
methamphetamine (Methedrine) are
collectively referred to as
amphetamines.
Benzedrine is a mixture of both the
dextro and levoamphetamine isomers. The
dextro isomer is several times more
potent than the levo isomer. |
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