Study Set Content:
an irreversible antagonist causes a downward shift of
the maximum, with no shift of the curve on the dose axis
unless spare receptors are present.
NONCOMPETITIVE ANTAGONIST
it cannot be overcome by adding more drug (agonist)
Noncompetitive agonist
HOW WILL THE MAXIMUM EFFICACY OF A DRUG BE
AFFECTED BY SUCH NONCOMPETITIVE ANTAGONISTS?
Maximum efficacy will be (blank) in the presence of a
noncompetitive antagonist.
reduced
ANTAGONIST can function non-competitively in a different way:
By binding to a site on the receptor protein (blank), and thereby modifying receptor activity
without blocking agonist binding
separate from the
agonist binding site
Although these drugs act non-competitively, their actions are
reversible
Although these drugs act non-competitively, their actions are
reversible. Such drugs are often called (blank) because they act by binding to a
different site on the receptors relative to the classical site
bound by the agonist.
negative allosteric modulators
Not all allosteric modulators act as antagonists, some
bind an allosteric site but, instead of inhibiting receptors
activation, (blank) it.
potentiate
Agonists can be divided into two classes:
Full agonists and partial agonist
a drug, when bound to a receptor
produces 100% of the maximum possible biologic
response.
Full agonist
drug that produces less than
100% of the maximum possible biologic response
no matter how high their concentration.
Partial agonists
It is important to emphasize that the failure of partial agonists to
produce a maximal response is not due to a(blank) for
binding to receptors.
decreased affinity
Partial agonists inability to cause a maximal pharmacologic
response, even when present at high concentrations that saturate
binding to all receptors, is indicated by the fact that partial
agonists (blank) the responses produced by full
agonists
competitively inhibit
One drug acts as a chemical antagonist of the other
simply by ionic binding that makes the other drug
unavailable for interaction with proteins involved in blood
clotting.
Chemical Antagonist
a protein that is positively charged at
physiologic pH,
Protamine,
an anticoagulant that is negatively
charged.
heparin
Protamine, a protein that is positively charged at
physiologic pH, can be used clinically to (blank) the
effects of heparin, an anticoagulant that is negatively
charged.
counteract
A drug that counters the effects of another by binding to a
different receptor and causing opposing effects.
Physiologic Antagonism
Between endogenous regulatory pathways mediated by different
receptors.
Physiologic Antagonism
Ex. Glucocorticoid hormones lead to increased blood sugar, an
effect that is physiologically opposed by
insulin
which is a physiological antagonist of the action of insulin
which results in insulin induced hypoglycemia.
Glucagon
