Research Square (Research Square),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Oct. 27, 2023
Abstract
6-Nitrodopamine
(6-ND)
is
released
from
isolated
atria
of
rabbit,
rat
and
mice
has
significant
positive
chronotropic
action.
The
effect
induced
by
6-ND
selectively
blocked
β1-adrenoceptor
antagonists
at
concentrations
that
do
not
affect
the
dopamine,
noradrenaline,
adrenaline.
Here
effects
propranolol,
4-NO2-propranolol
7-NO2-propranolol
were
investigated
in
right
atrium.
atrium
was
mounted
between
two
metal
hooks
10-mL
custom
designed
glass
chambers
containing
Krebs-Henseleit’s
solution,
continuously
gassed
(95%O2:5%CO2)
heated
(37°C).
Tissues
allowed
to
equilibrate
under
a
resting
tension
10
mN
for
one
hour,
isometric
registered
using
PowerLab
system.
4-NO2-propranol
more
potent
than
propranolol
as
negative
agent.
At
30
nM,
did
S-isomer
4-
NO2-propranolol,
but
R-isomer,
active.
Propranolol
fall
atrial
rate
higher
those
required
block
noradrenaline
adrenaline,
enough
effect.
only
active
very
high
concentration,
stereoselective.
(100
nM)
(300
observed
L-NAME
treated
atria,
whereas
(10
mM)
unaffected.
selective
inhibition
with
(±)-4-NO2-propranolol
reinforces
concept
major
mediator
heart
chronotropism
main
target
so-called
b-blockers.
Physiology,
Journal Year:
2023,
Volume and Issue:
39(1), P. 44 - 59
Published: Oct. 24, 2023
The
review
deals
with
the
release
of
endothelium-derived
dopamine
and
6-nitrodopamine
(6-ND)
its
effects
on
isolated
vascular
tissues
hearts.
Basal
both
6-ND
is
present
in
human
umbilical
cord
vessels,
popliteal
nonhuman
primate
reptilia
aortas.
basal
was
significantly
reduced
when
were
treated
Life,
Journal Year:
2023,
Volume and Issue:
13(10), P. 2012 - 2012
Published: Oct. 4, 2023
Background:
6-nitrodopamine
released
from
rat
isolated
atria
exerts
positive
chronotropic
action,
being
more
potent
than
noradrenaline,
adrenaline,
and
dopamine.
Here,
we
determined
whether
is
ventricles
(RIV)
modulates
heart
inotropism.
Methods:
Catecholamines
RIV
were
quantified
by
LC-MS/MS
their
effects
on
inotropism
evaluated
measuring
left
ventricular
developed
pressure
(LVDP)
in
Langendorff’s
preparation.
Results:
was
the
major
catecholamine
RIV.
Incubation
with
L-NAME
(100
µM),
but
not
tetrodotoxin
(1
caused
a
significant
reduction
basal
release.
release
significantly
reduced
obtained
chronically
treated
animals.
(0.01
pmol)
increases
LVDP
dP/dtmax,
whereas
dopamine
noradrenaline
required
10
pmol,
adrenaline
100
to
induce
similar
dP/dtmax.
The
infusion
of
atenolol
(10
nM)
blocked
induced
6-ND
pmol),
without
affecting
nmol
that
nmol).
Conclusions:
ventricles.
It
1000
times
selectively
atenolol,
indicating
main
regulator
Frontiers in Pharmacology,
Journal Year:
2024,
Volume and Issue:
15
Published: April 5, 2024
Introduction:
The
human
umbilical
artery
(HUA),
rat-isolated
right
atrium,
and
vas
deferens
present
a
basal
release
of
6-nitrodopamine
(6-ND).
6-ND
from
these
tissues
was
significantly
decreased
(but
not
abolished)
when
the
were
pre-incubated
with
N
ω
-nitro-L-arginine
methyl
ester
(L-NAME).
Methods:
In
this
study,
effect
pharmacological
modulation
redox
environment
on
investigated.
measured
using
Liquid
chromatography
tandem
mass
spectrometry
(LC-MS/MS).
Results
Discussion:
Pre-incubation
(30
min)
GKT137831
(1
μM)
caused
significant
increase
in
all
tissues.
HUA,
pre-incubation
diphenyleneiodonium
(DPI)
(100
also
increases
6-ND.
Preincubation
HUA
hydrogen
peroxide
(H
2
O
)
increased
release,
whereas
catalase
(1,000
U/mL)
it.
superoxide
dismutase
(SOD)
(250
U/mL;
30
either
allopurinol
or
uric
acid
mM)
had
no
Pre-treatment
L-NAME
prevented
induced
by
GKT137831,
diphenyleneiodonium,
H
.
results
obtained
indicate
major
role
endogenous
H2O2
peroxidases
as
modulators
6-
ND
biosynthesis/release
lack
peroxynitrite
contribution.
Research Square (Research Square),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Feb. 23, 2024
Abstract
6-Nitrodopamine
(6-ND)
is
released
from
rat
isolated
atria
and
has
positive
chronotropic
action,
which
selectively
blocked
by
β
1
-adrenoceptor
antagonists
at
concentrations
that
do
not
affect
the
effect
induced
dopamine,
noradrenaline,
adrenaline.
Here
effects
of
(±)-propranolol,
(±)-4-NO
2
-propranolol,
(±)-7-NO
were
investigated
in
right
atrium.
The
atrium
was
mounted
gassed
(95%O
:5%CO
),
heated
(37°C)
glass
chambers,
containing
Krebs-Henseleit’s
solution.
Tissues
allowed
to
equilibrate
under
a
resting
tension
10mN
for
hour,
isometric
registered
using
PowerLab
system.
-propranolol
caused
concentration-dependent
falls
spontaneous
atrial
frequency
(pEC
50
4.80
±
0.10,
4.64
4.95
respectively).
Noradrenaline
(1nM–30µM),
adrenaline
(1nM–100µM),
increases
rate.
calculated
pA
values
-propranol
obtained
noradrenaline-induced
8.21
0.35,
6.41
0.21,
8.35
respectively.
6-ND
(10pM)
(±)-propranolol
(1µM),
(30nM).
(1µM)
had
no
on
(10pM)-induced
pEC
significantly
shifted
L-NAME
treated
atria.
discrepancy
between
its
respective
indicates
rate
should
be
attributed
b-adrenergic
antagonism.
finding
causes
only
effect,
confirms
role
this
catecholamine
as
endogenous
modulator
heart
chronotropism.
Research Square (Research Square),
Journal Year:
2024,
Volume and Issue:
unknown
Published: July 29, 2024
Abstract
The
positive
chronotropic
action
induced
by
6-mitrodopamine
(6-ND)
is
selectively
blocked
β1-adrenoceptor
antagonists
at
concentrations
that
do
not
affect
the
effect
dopamine,
noradrenaline,
and
adrenaline.
Here
effects
of
(±)-propranolol,
(±)-4-NO2-propranolol,
(±)-7-NO2-propranolol,
were
investigated
in
rat
isolated
right
atrium.
atrium
was
mounted
glass
chambers
containing
gassed
(95%O2:5%CO2)
warmed
(37°C)
Krebs-Henseleit’s
solution,
isometric
tension
registered
(PowerLab
system).
(±)-4-NO2-propranolol
caused
concentration-dependent
falls
spontaneous
atrial
frequency
(pIC50
4.80±0.10,
4.64±0.10,
4.95±0.10,
respectively).
calculated
pA2
values
for
(±)-7-NO2-propranol
obtained
noradrenaline-induced
8.44±0.08,
6.41±0.07,
9.21±0.29,
respectively.
chronotropism
6-ND
(10pM)
(±)-propranolol
(1mM),
(30nM).
(1mM)
had
no
on
(10pM)-induced
increases
rate.
pIC50
(±)-7-NO2-propranolol
significantly
shifted
to
L-NAME
treated
atria.
discrepancy
between
its
respective
indicates
rate
should
be
attributed
b-adrenergic
antagonism.
reduced
(10µM)
unaffected
sodium
channel
inhibitors
tetrodotoxin
(1µM)
lidocaine
but
abolished
atria
pre-treated
with
(10µM).
finding
causes
only
effect,
confirms
role
this
catecholamine
as
endogenous
modulator
heart
chronotropism.
behaves
a
selective
antagonist
Research Square (Research Square),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Nov. 26, 2024
AbstractPurpose-
Rat
isolated
atria
and
ventricles
releases
endothelium-derived
6-nitrodopamine
this
novel
catecholamine
induces
a
potent
endogenous
positive
chronotropic
inotropic
response.
6-Cyanodopamine
is
released
from
rabbit
ventricles,
however
it
not
known
whether
has
any
action
on
the
heart.
Therefore,
was
investigated
rat
release
6-cyanodopamine
its
Methods-
Basal
of
assessed
by
LC-MS/MS
tyrosine
hydroxylase
both
immunohistochemistry
fluorescence
in
situ
hybridization.
Chronotropic
effects
were
evaluated
in
Langendorff’s
preparation,
respectively.
Results-
presented
basal
6-cyanodopamine,
which
unaffected
pre-treatment
with
tetrodotoxin.
Immunohistochemistry
hybridization
identified
expression
endothelium
cardiomyocytes.
at
10
100
pM
induced
increases
atrial
rate,
maintained
even
30min
after
preparation
washed.
In
1min
infusion
(10
100pM)
significantly
increased
heart
frequency,
LVDP,
dP/dt(max).
Bolus
injection
noradrenaline
(1pmol)
had
no
effect
LVDP
dPdt(max).
Infusion
(0.01pM)
dP/dt(max)
when
injected
end
infusion.
Conclusion-
The
results
indicate
that
mediator
chronotropism
inotropism
It
potential
therapeutic
failure
may
be
useful
as
biomarker
pathophysiological
processes.
