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Brain Research Bulletin,Vol. 28, pp. 161-168, 1992 Printed in the USA. All rights reserved.
Copyright
0 1992 Pergamon
Press Ltd.
Effect of Atria1 Natriuretic Peptide on DOPA Potentiation in Mice AMELIA BIDZSERANOVA,*
JONY GUERON,* GABOR TbTH,? AND GYULA TELEGDY*’
BOTOND
PENKEt
*Institute of Pathophysiology and fkstitute of Medical Chemistry, Albert Szent-GyiirgyiMedical University,Szeged, Hungary Received 6 May 199 1 BIDZSERANOVA, A., J. GUERON, G. TGTH, B. PENKE AND G. TELEGDY. Effecf of afriul nnfriurefic pepfide on DUPA effect of rat atria1 natriuretic peptide (ANPI& on the pargyline-DOPA potentiation test was studied following its administration into the lateral brain ventricle in mice. Thirty minutes after pargyline pretreatment, three doses of ANP (200, 500, or 1,000 rig/mouse) were administered simultaneously with DOPA and animals were then observed for 2 h. ANP in doses of 500 and 1,000ng markedly enhanced the effect of DOPA. The maximum intensity of the effect was registered 30-45 min following administration of the peptide. The data suggest that ANP might be regarded as a dopaminergic-modulating agent in the CNS.
pofenfiafion in mice. BRAIN RES BULL 28(5) 767-768, 1992.-The
Atria1 natriuretic peptide
Pargyline
DOPA potentiation -
The DOPA response potentiation test in mice, as developed and described by Plotnikoff et al (lo), was used with modification to have a quantitative evaluation for statistical analysis. The method consists of pretreating animals with pargyline HCl (40 mg/kg, IP) (6,lO) 30 min before DOPA and then observing them for l-2 h. Observation was done in a double-blind manner and the behavior was scored every 15 min. Potentiation of the DOPAinduced response was scored by means of the changes in the expression of five different indexes-piloerection, salivation, jumping, squeaking, and aggressive fightings-using a four-degree scoring scale for each of them (0 stands for no DOPA effect, 1 for slight DOPA effect, 2 for moderate one, and 3 for marked
IN previous experiments, we demonstrated that atrial natriuretic peptide (ANP) participates in fear-induced learning processes
via dopaminergic and cholinergic mediation (1,4,5). We confirmed the supposition that ANP might be considered a modulatory peptide of dopamine (DA) mediation by describing its effect on apomorphine-induced stereotyped cage-climbing behavior in rats (2). The present work provides more experimental data in this respect. The effect of ANP on pargyline-DOPA potentiation in mice was studied following its administration into the lateral brain ventricle. The pargyline-DOPA mouse test of Plotnikoffet al. (9), which has been used to screen new substances for antidepressant action, was explored to demonstrate the effect of ANP on DA mediation. METHOD
TABLE 1
Adult CFLP mice of an inbred strain were used. Animals weighed 25-30 g and were housed 10 per cage. They had access to commercial food and tapwater ad lib and were kept on a standard 12 L:12 D cycle (lights on at 6:00 a.m.). Experiments were carried out daily between 8:00 a.m. and noon. Mice were anesthetized with pentobarbital-Na (nembutal, 35 mg/kg, IP) and a cannula was placed into the right lateral cerebroventricle and fixed to the skull with dental cement. Animals were used 5 days following operation. The correct positioning of the cannula was checked individually by injection of methylene blue after experiments had been completed. Only those with right positioning of the cannula were included in the statistical evaluation.
SCHEME
OF TREATMENTS FOR MEASURING POTENTIATION IN MICE Treatment
Groups
Control 200 ng ANP 500 ng ANP 1,000 ng ANP
DOPA
(min)
0
30
30-150
Paragyline* Paragyline Paragyline Paragyline
DOPAt + saline DOPA + ANP DOPA + ANP DOPA + ANP
Testing Testing Testing Testing
* Paragyline 40 mg/kg IP. t L-DOPA 100 mg/kg IP.
’ Requests for reprints should be addressed to Gyula Telegdy, Institute of Pathophysiology, A. Szent-Gyorgyi Medical University, Semmelweis u. 1, POB 531, Szeged 6701, Hungary.
767
BIDZSERANOVA
ET AL.
TABLE 2 EFFECT
OF ANP ON DOPA
POTENTIATION
IN MICE
Test Periods (min) rANP,.,, (ng/mouse,
ICV)
n
Control
24
200 500 1000
16 16 16
45
0.63 * 0.75 + 0.94 f 1.70 f
60
0.16 0.18 0.17* 0.15*
0.79 f l.OO? 1.88 * 2.75 +
75
0.16 0.16 0.20* O.ll*
1.46 + 1.69f 2.75 + 2.81 *
90
0.23 0.24 0.1 l* 0.10*
1.41 + 1.43+ 2.25 * 2.13 +
120
0.23 0.20 0.17* O.l8*
0.63 + 0.94 * 1.19 + 1.75 f
0.13 0.14 0.16* 0.17*
150
0.00 0.00 0.38 0.75
It + + f
0.00 0.00 0.18* 0.14*
Data are means + SEM of individual scores. * p < 0.05 vs. control (ANOVA, Dunnett).
one). The response of animals from the control group (treated with pargyline, DOPA, and saline), consisting of piloerection and slight salivation, was scored as a behavioral rating of 1. Moderate and marked increase in the above-mentioned activities were scored with 2 and 3, respectively. When there was no DOPA effect observed or it disappeared, the score was 0. For convenience in the statistical evaluation, the individual data are given as mean of all five index scores. Rat ANPI_ was purchased from Bachem (Bubendorf, Switzerland) and also synthesized by two of us (G.T. and B.P.). The peptide was dissolved in 0.9% saline and administered in doses of 200, 500, or 1,000 ng per animal in a volume of 2 ~1 ICV to freely moving animals simultaneously with L-DOPA (EGYS, Budapest) ( 100 mg/kg, IP). The control group received the same amount of 2 ~1 ICV saline and L-DOPA (10). Statistical analysis of the results was performed by analysis of variance (ANOVA), followed by Dunnett’s test. RESULTS
Table 1 shows the scheme of treatment in the different groups. The entire experiment lasted 150 min. Animals were observed for 120 min in their home cages. The effect of three doses of ANP on the DOPA potentiation test is demonstrated in Table 2. The dose of 200 ng had almost no influence on the behavior of mice. The doses of 500 and 1,000 ng ANP effectively potentiated the DOPA response, with maximal intensity of the increase 30-45 min following administration of the peptide [ANOVA, F(3, 7) = 26.7 and F(3, 7) = 13.3, p = 0.0001, Dunnett test, p < 0.05 vs. control]. Forty-five minutes after administration of ANP, the effect gradually de-
clined and at the end of the first hour of observation only a slight (500 ng) or moderate-slight (1,000 ng) increase remained. At the end of the second hour, there was still a slight degree of DOPA potentiation at the highest dose.
DISCUSSION
In the present study, ANP administered intracerebroventricularly in doses of 500 or 1,000 rig/moose was found active in the DOPA potentiation test. Our earlier studies suggested ANP might exert a modulatory effect in the processes of fear-induced learning via dopaminergic mediation (1,4,5). This peptide potentiated the effect of apomorphine (a DA agonist) in inducing stereotyped cage-climbing behavior in mice (2). All effects of ANP studied by us could be blocked by haloperidol (a DA blocking agent) (1,3,5). Others also reported a DA blockade on central and peripheral effects of the peptide (7,8). Little is known about the mechanism in which ANP interacts with the dopaminergic neurotransmission. ANP may act preor postsynaptically on dopaminergic neurons in the hypothalamus or other brain structures to augment the combined effects of pargyline-DOPA. It may interact with dopaminergic receptors in appropriate brain structures involved in the performance of the DOPA potentiation test. There is no literature available answering this question at present time. Our data confirm our earlier observations that the action of ANP on active and passive avoidance behavior is mediated via dopaminergic transmission (1,3,5); however, the actual site of its action, that is, whether it is acting pre- or postsynaptically or at receptor site, remains to be clarified.
REFERENCES 1. Bidzseranova, A.; Gueron, J.; Penke, B.; Telegdy, G. The effects of atria1 natriuretic peptide on active avoidance behavior in rats. The role of the transmitter systems. Pharmacol. Biochem. Behav. 40: 61-64; 1991. 2. Bidzseranova, A.; Gueron, J.; T&h, G.; Penke, B.; Telegdy, G. Effect of atria1 natriuretic peptide on apomorphine-induced stereotyped cage-climbing behavior in mice. Eur. J. Pharmacol. (in press). 3. Bidzseranova, A.; Penke, B.; Telegdy, G. The effects of atria1 natriuretic peptide on electroconvulsive shock-induced amnesia inrats: Transmitter mediated action. Neuropeptides 19:103- 106;1990. 4. Bidzseranova, A.; Telegdy, G.; Penke, B. The effects of atria1 natriuretic peptide on passive avoidance behavior in rats. Brain Res. Bull. 26:177-180; 1991. 5. Bidzseranova, A.; Telegdy, G.; Tbth, G. The effects of receptor blockers on atrial natriuretic peptide-induced action on passive avoidance behavior in rats. Pharmacol. Biochem. Behav. 40:237239; 1991.
6. Fekete, M.; Telegdy, G.; Schally, A. V.; Coy, D. Effects of@/TYR9/ melanotropin-/9- 18/ decapeptide on catecholamine disappearance and serotonin accumulation in discrete brain regions of rats. Neuropeptides 1:377-382; 1981. Israel, A.: Torres, M.; Barbella, Y. Evidence for a dopaminergic mechanism for the diuretic and natriuretic action of centrally administered atria1 natriuretic factor. Cell Mol. Neurobiol. 9(3):365378; 1989. Marin-Grez, M.; Brings, I. P.; Schubert, G.; Schnermann, J. Dopamine receptor antagonists inhibit the natriuretic response to atria1 natriuretic factor (ANF). Life Sci. 36:2 17l-2 176; 1985. Plotnikoff, N. P.; Kastin, A.; Anderson, M.; Schally, A. DOPA potentiation by a hypothalamic factor, MSH release-inhibiting hormone (MIF). Life Sci. l&1279-1283; 1971. IO. Plotnikoff, N. P.; Prange, A.; Breese, G.; Wilson, 1. Thyrotropin releasing hormone: Enhancement of DOPA activity in thyroidectomized rats. Life Sci. 14:1271-1278; 1974.
Brain Research Bulletin,Vol. 28, pp. 161-168, 1992 Printed in the USA. All rights reserved.
Copyright
0 1992 Pergamon
Press Ltd.
Effect of Atria1 Natriuretic Peptide on DOPA Potentiation in Mice AMELIA BIDZSERANOVA,*
JONY GUERON,* GABOR TbTH,? AND GYULA TELEGDY*’
BOTOND
PENKEt
*Institute of Pathophysiology and fkstitute of Medical Chemistry, Albert Szent-GyiirgyiMedical University,Szeged, Hungary Received 6 May 199 1 BIDZSERANOVA, A., J. GUERON, G. TGTH, B. PENKE AND G. TELEGDY. Effecf of afriul nnfriurefic pepfide on DUPA effect of rat atria1 natriuretic peptide (ANPI& on the pargyline-DOPA potentiation test was studied following its administration into the lateral brain ventricle in mice. Thirty minutes after pargyline pretreatment, three doses of ANP (200, 500, or 1,000 rig/mouse) were administered simultaneously with DOPA and animals were then observed for 2 h. ANP in doses of 500 and 1,000ng markedly enhanced the effect of DOPA. The maximum intensity of the effect was registered 30-45 min following administration of the peptide. The data suggest that ANP might be regarded as a dopaminergic-modulating agent in the CNS.
pofenfiafion in mice. BRAIN RES BULL 28(5) 767-768, 1992.-The
Atria1 natriuretic peptide
Pargyline
DOPA potentiation -
The DOPA response potentiation test in mice, as developed and described by Plotnikoff et al (lo), was used with modification to have a quantitative evaluation for statistical analysis. The method consists of pretreating animals with pargyline HCl (40 mg/kg, IP) (6,lO) 30 min before DOPA and then observing them for l-2 h. Observation was done in a double-blind manner and the behavior was scored every 15 min. Potentiation of the DOPAinduced response was scored by means of the changes in the expression of five different indexes-piloerection, salivation, jumping, squeaking, and aggressive fightings-using a four-degree scoring scale for each of them (0 stands for no DOPA effect, 1 for slight DOPA effect, 2 for moderate one, and 3 for marked
IN previous experiments, we demonstrated that atrial natriuretic peptide (ANP) participates in fear-induced learning processes
via dopaminergic and cholinergic mediation (1,4,5). We confirmed the supposition that ANP might be considered a modulatory peptide of dopamine (DA) mediation by describing its effect on apomorphine-induced stereotyped cage-climbing behavior in rats (2). The present work provides more experimental data in this respect. The effect of ANP on pargyline-DOPA potentiation in mice was studied following its administration into the lateral brain ventricle. The pargyline-DOPA mouse test of Plotnikoffet al. (9), which has been used to screen new substances for antidepressant action, was explored to demonstrate the effect of ANP on DA mediation. METHOD
TABLE 1
Adult CFLP mice of an inbred strain were used. Animals weighed 25-30 g and were housed 10 per cage. They had access to commercial food and tapwater ad lib and were kept on a standard 12 L:12 D cycle (lights on at 6:00 a.m.). Experiments were carried out daily between 8:00 a.m. and noon. Mice were anesthetized with pentobarbital-Na (nembutal, 35 mg/kg, IP) and a cannula was placed into the right lateral cerebroventricle and fixed to the skull with dental cement. Animals were used 5 days following operation. The correct positioning of the cannula was checked individually by injection of methylene blue after experiments had been completed. Only those with right positioning of the cannula were included in the statistical evaluation.
SCHEME
OF TREATMENTS FOR MEASURING POTENTIATION IN MICE Treatment
Groups
Control 200 ng ANP 500 ng ANP 1,000 ng ANP
DOPA
(min)
0
30
30-150
Paragyline* Paragyline Paragyline Paragyline
DOPAt + saline DOPA + ANP DOPA + ANP DOPA + ANP
Testing Testing Testing Testing
* Paragyline 40 mg/kg IP. t L-DOPA 100 mg/kg IP.
’ Requests for reprints should be addressed to Gyula Telegdy, Institute of Pathophysiology, A. Szent-Gyorgyi Medical University, Semmelweis u. 1, POB 531, Szeged 6701, Hungary.
767
BIDZSERANOVA
ET AL.
TABLE 2 EFFECT
OF ANP ON DOPA
POTENTIATION
IN MICE
Test Periods (min) rANP,.,, (ng/mouse,
ICV)
n
Control
24
200 500 1000
16 16 16
45
0.63 * 0.75 + 0.94 f 1.70 f
60
0.16 0.18 0.17* 0.15*
0.79 f l.OO? 1.88 * 2.75 +
75
0.16 0.16 0.20* O.ll*
1.46 + 1.69f 2.75 + 2.81 *
90
0.23 0.24 0.1 l* 0.10*
1.41 + 1.43+ 2.25 * 2.13 +
120
0.23 0.20 0.17* O.l8*
0.63 + 0.94 * 1.19 + 1.75 f
0.13 0.14 0.16* 0.17*
150
0.00 0.00 0.38 0.75
It + + f
0.00 0.00 0.18* 0.14*
Data are means + SEM of individual scores. * p < 0.05 vs. control (ANOVA, Dunnett).
one). The response of animals from the control group (treated with pargyline, DOPA, and saline), consisting of piloerection and slight salivation, was scored as a behavioral rating of 1. Moderate and marked increase in the above-mentioned activities were scored with 2 and 3, respectively. When there was no DOPA effect observed or it disappeared, the score was 0. For convenience in the statistical evaluation, the individual data are given as mean of all five index scores. Rat ANPI_ was purchased from Bachem (Bubendorf, Switzerland) and also synthesized by two of us (G.T. and B.P.). The peptide was dissolved in 0.9% saline and administered in doses of 200, 500, or 1,000 ng per animal in a volume of 2 ~1 ICV to freely moving animals simultaneously with L-DOPA (EGYS, Budapest) ( 100 mg/kg, IP). The control group received the same amount of 2 ~1 ICV saline and L-DOPA (10). Statistical analysis of the results was performed by analysis of variance (ANOVA), followed by Dunnett’s test. RESULTS
Table 1 shows the scheme of treatment in the different groups. The entire experiment lasted 150 min. Animals were observed for 120 min in their home cages. The effect of three doses of ANP on the DOPA potentiation test is demonstrated in Table 2. The dose of 200 ng had almost no influence on the behavior of mice. The doses of 500 and 1,000 ng ANP effectively potentiated the DOPA response, with maximal intensity of the increase 30-45 min following administration of the peptide [ANOVA, F(3, 7) = 26.7 and F(3, 7) = 13.3, p = 0.0001, Dunnett test, p < 0.05 vs. control]. Forty-five minutes after administration of ANP, the effect gradually de-
clined and at the end of the first hour of observation only a slight (500 ng) or moderate-slight (1,000 ng) increase remained. At the end of the second hour, there was still a slight degree of DOPA potentiation at the highest dose.
DISCUSSION
In the present study, ANP administered intracerebroventricularly in doses of 500 or 1,000 rig/moose was found active in the DOPA potentiation test. Our earlier studies suggested ANP might exert a modulatory effect in the processes of fear-induced learning via dopaminergic mediation (1,4,5). This peptide potentiated the effect of apomorphine (a DA agonist) in inducing stereotyped cage-climbing behavior in mice (2). All effects of ANP studied by us could be blocked by haloperidol (a DA blocking agent) (1,3,5). Others also reported a DA blockade on central and peripheral effects of the peptide (7,8). Little is known about the mechanism in which ANP interacts with the dopaminergic neurotransmission. ANP may act preor postsynaptically on dopaminergic neurons in the hypothalamus or other brain structures to augment the combined effects of pargyline-DOPA. It may interact with dopaminergic receptors in appropriate brain structures involved in the performance of the DOPA potentiation test. There is no literature available answering this question at present time. Our data confirm our earlier observations that the action of ANP on active and passive avoidance behavior is mediated via dopaminergic transmission (1,3,5); however, the actual site of its action, that is, whether it is acting pre- or postsynaptically or at receptor site, remains to be clarified.
REFERENCES 1. Bidzseranova, A.; Gueron, J.; Penke, B.; Telegdy, G. The effects of atria1 natriuretic peptide on active avoidance behavior in rats. The role of the transmitter systems. Pharmacol. Biochem. Behav. 40: 61-64; 1991. 2. Bidzseranova, A.; Gueron, J.; T&h, G.; Penke, B.; Telegdy, G. Effect of atria1 natriuretic peptide on apomorphine-induced stereotyped cage-climbing behavior in mice. Eur. J. Pharmacol. (in press). 3. Bidzseranova, A.; Penke, B.; Telegdy, G. The effects of atria1 natriuretic peptide on electroconvulsive shock-induced amnesia inrats: Transmitter mediated action. Neuropeptides 19:103- 106;1990. 4. Bidzseranova, A.; Telegdy, G.; Penke, B. The effects of atria1 natriuretic peptide on passive avoidance behavior in rats. Brain Res. Bull. 26:177-180; 1991. 5. Bidzseranova, A.; Telegdy, G.; Tbth, G. The effects of receptor blockers on atrial natriuretic peptide-induced action on passive avoidance behavior in rats. Pharmacol. Biochem. Behav. 40:237239; 1991.
6. Fekete, M.; Telegdy, G.; Schally, A. V.; Coy, D. Effects of@/TYR9/ melanotropin-/9- 18/ decapeptide on catecholamine disappearance and serotonin accumulation in discrete brain regions of rats. Neuropeptides 1:377-382; 1981. Israel, A.: Torres, M.; Barbella, Y. Evidence for a dopaminergic mechanism for the diuretic and natriuretic action of centrally administered atria1 natriuretic factor. Cell Mol. Neurobiol. 9(3):365378; 1989. Marin-Grez, M.; Brings, I. P.; Schubert, G.; Schnermann, J. Dopamine receptor antagonists inhibit the natriuretic response to atria1 natriuretic factor (ANF). Life Sci. 36:2 17l-2 176; 1985. Plotnikoff, N. P.; Kastin, A.; Anderson, M.; Schally, A. DOPA potentiation by a hypothalamic factor, MSH release-inhibiting hormone (MIF). Life Sci. l&1279-1283; 1971. IO. Plotnikoff, N. P.; Prange, A.; Breese, G.; Wilson, 1. Thyrotropin releasing hormone: Enhancement of DOPA activity in thyroidectomized rats. Life Sci. 14:1271-1278; 1974.
