3 research outputs found
Effects of ICI 118.551, a selective beta-2 adrenergic blocking agent on the guinea pig cardic excitability and ventricular fibrillation threshold
In
isolated
guinea
pig
perfused
hearts
ICI
118.551,
a
selective
beta
2
adrenoceptor
antagonist,
induced
transient
ventricular
extrasystoles.
Following
the
termination
of
the
perfusion,
a
very
significant
increase
of
both
the
ventricular
fibrillation
threshold
and
the
refractory
periods
were
measured.
In
guanethidine
pretreated
hearts,
ICI
118.551
failed
to
induce
premature
beats.
At
the
same
time
the
fibrillation
threshold
and
refractory
periods
exhibited
a
very
significant
decrease.
The
perfusion
of
equimolecular
concentration
of
metoprolol,
a
beta-1-adrenoceptor
antagonist,
and
(+)
propranolol,
a
quinidine-like
compound,
induced,
in
most
experimental
settings,
similar
results
as
ICI
118.551.
Thus,
besides
its
beta-2-adrenoceptor
antagonist
properties,
ICI
118.551
presented
other
pharmacological
actions