25 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
Effects of zopiclone on blood glucose level, serum lipid concentration and clot lysis time normoglycemic and normolipidemic rats
In normoglycemic and normolipidemic rats the i.p. injection of zopiclone induced an acceleration of fibrinolysis in a dose-dependent bell shaped manner and various changes of the blood glucose level. Total lipids, total cholesterol and triglyceride serum levels remained unaffected by doses of 1.25, 2.5 and 15.0 mg/kg, with the exception of the medium dose (5.0 mg/kg) and the next dose (10.0 mg/kg) which lowered them very significantlly
The influance of intracerebroentricular administration of (±)propanol and(±)verapamil on experimental myocardial ischemia and necrosis in rats
In
albino
rats,
infarctoid
myocardial
lesions
were
produced
by
intraperitoneal
(i.p.)
administration
of
isoproterenol
(75
mg/kg,
during
3
days).
In
other
groups,
the
descending
anterior
left
coronary
artery
was
ligated.
In
both
experimental
settings,
the
intracerebroventricular
(i.c.v.)
administration
of
(
±
)
propranolol
(100-200-300
μ
g/animal/day,
during
7
days)
or
(
±
)
verapamil
(40-80-160
μ
g/animal/day,
during
7
days)
afforded
a
significant
protection
(with
the
exception
of
the
lowest
dose)
on
the
investigated
parameters:
arrhythmias,
ischemic
zone
(in
coronary
ligated
rats),
lactate
dehydrogenase
and
aspartate
aminotransferase
activity
of
the
serum,
focal
necrosis
(in
isoproterenol
treated
rats).
This
protective
activity
is
lower
than
that
afforded
by
i.p.
administered
(±)
propranolol
(5
mg/kg,
during
seven
days)
or
(±)
verapamil
(5
mg/kg,
during
seven
days).
From
these
data
it
may
be
concluded
that
(±)
propranolol
and
(±)
verapamil
have
a
protective
action
on
the
experimental
myocardial
ischemia
and
necrosis
in
rats,
not
only
when
the
drugs
come
in
direct
contact
with
the
heart,
but
also
acting
upon
the
central
nervous
system
Central arrhythmogenic effects of N-methyl-D-aspartate (NMDA) in anesthetized rats: influence of the denervation of the carotid-sinus baroreceptors on the susceptibility to arrhythmias
Wir besprechen ein Demonstrationsexperiment zur Induktion, das zu paradoxen Spannungsmessungen führt, und zeigen die Problematik einer rein formalen Erklärung auf. Um ein tieferes Verständnis zu ermöglichen, stellen wir ergänzende Versuchsanordnungen vor. Diese erlauben es, die Verteilung induzierter elektromotorischer Kräfte in homogenen wie inhomogenen Leitern nachzuweisen. Sie machen deutlich, was man mit Voltmetern an Anordnungen mißt, die zeitlich veränderlichen elektromagnetischen Feldern ausgesetzt sind
Effects of the intracerebroventricular administration of ketamine on centrogenic arrhythmias in anesthetized rats.
In urethane anesthetized rats the icv (lateral cerebral ventricle) administration of ketamine, at the highest utilized doses, induced bradypnea and sinus bradycardia in spontaneously breathing rats. Moreover, it partially antagonized the arrhythmogenic activities of sodium glutamate and sodium aspartate, as well as desipramine and ouabain. From these results, we conclude that ketamine had an inhibitory effect on the centrogenic arrhythmias not only acting at the level of NMDA subtype receptor, but also at beta 1 adrenergic central receptors. Moreover at high doses, ketamine can also induce centrogenic arrhythmias in spontaneously breathing rats