Study Set Content:
The accidental ingestion of ergot alkaloids in
contaminated grain can be traced back more
than 2000 years from descriptions of epidemics
of ergot poisoning (ergotism)- was called
St.
Anthony's fire.
effects of poisoning:
dementia with
florid hallucinations
prolonged vasospasm, which may
result in
gangrene;
stimulation of uterine smooth muscle,
which in pregnancy may result in
abortion
Two major families of compounds that incorporate the
tetracyclic ergoline nucleus may be identified;
amine alkaloids and
- the peptide alkaloids
are variably absorbed
from the gastrointestinal tract.
ergot alkaloids
The oral dose of ergotamine is about (blank) larger than
the intramuscular dose,
10 times
The oral dose of ergotamine is about 10 times larger than
the intramuscular dose, but the speed of absorption and
peak blood levels after oral administration can be
improved by administration with
caffeine
The amine alkaloids are also absorbed from the rectum
and the buccal cavity and after administration by
aerosol inhaler.
Absorption after intramuscular injection is(blank) but usually
reliable.
slow
Semisynthetic analogs such as (blank) and
(blank) are well absorbed from the gastrointestinal
tract.
bromocriptine and
cabergoline
The ergot alkaloids act on several types of
receptors.
• As shown by the color outlines in Table 16-7, the
nuclei of both catecholamines phenylethylamine,
left panel) and 5-HT (indole, right panel) can be
discerned in the
ergoline nucleus
Their effects include(blank) at a adrenoceptors and
serotonin receptors
agonist, partial agonist, and
antagonist actions
effects at central nervous system dopamine receptors
agonist
or partial agonist
Furthermore, some members of the ergot family
have a high affinity for
presynaptic receptors,
Furthermore, some members of the ergot family
have a high affinity for presynaptic receptors,
whereas others are more selective for
postjunctional receptors.
There is a powerful stimulant effect on the
uterus that seems to be most closely associated
with agonist or partial agonist effects at
5-HT 2
receptors.
alkaloids are powerful
hallucinogens.
is a
synthetic ergot compound that clearly
demonstrates this action.
Lysergic acid diethylamide (LSD)
Abuse of this drug has waxed and waned but is
still
widespread
