Naloxone-induced Jumping In Morphine-dependent Mice Research Articles

Sintocalmy, a Passiflora incarnata Based Herbal, Attenuates Morphine Withdrawal in Mice.

Chronic opioid use changes brain chemistry in areas related to reward processes, memory, decision-making, and addiction. Both neurons and astrocytes are affected, ultimately leading to dependence. Passiflora incarnata L. (Passifloraceae) is the basis of frequently used herbals to manage anxiety and insomnia, with proven central nervous system depressant effects. Anti-addiction properties of P. incarnata have been reported. The aim of this study was to investigate the effect of a commercial extract of Passiflora incarnata (Sintocalmy®, Aché Laboratory) in the naloxone-induced jumping mice model of morphine withdrawal. In addition, glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B) levels were assessed in the frontal cortex and hippocampus, and DNA damage was verified on blood cells. In order to improve solubilization a Sintocalmy methanol extract (SME) was used. SME is mainly composed by flavonoids isovitexin and vitexin. The effects of SME 50, 100 and 200mg/kg (i.p.) were evaluated in the naloxone-induced withdrawal syndrome in mice. SME 50 and SME 100mg/kg decreased naloxone-induced jumping in morphine-dependent mice without reducing locomotor activity. No alterations were found in GFAP levels, however SME 50mg/kg prevented the S100B increase in the frontal cortex and DNA damage. This study shows anti-addiction effects for a commercial standardized extract of P. incarnata and suggests the relevance of proper clinical assessment.

Conantokins and variants derived from cone snail venom inhibit naloxone-induced withdrawal jumping in morphine-dependent mice

The biochemical processes underlying opiate addiction are complex, but n-methyl- d-aspartate receptor (NMDAR) dysfunction appears to be one contributing factor. NMDAR antagonists, including MK-801 and memantine, have previously been shown to assuage symptoms stemming from opiate withdrawal. The conantokins are a small family of naturally occurring peptide toxins known to specifically antagonize the NMDAR. In the present study, the effects of wild-type and variant conantokins on the suppression of naloxone-induced jumping in morphine-dependent mice were evaluated. Our results demonstrate that NR2B-selective conantokins, viz., con-G, con-G[S 16Y] and con-G[γ 7K], are potent inhibitors of naloxone-induced jumping at low doses (2–15 nmol/kg) compared with con-T, con-R[1-17], and small-molecule antagonists of the NMDAR, including the NR2B-selective agent, ifenprodil. We conclude that the NR2B-selective conantokins may find utility as neuropharmacological tools for probing NMDAR-related mechanisms of opiate dependence.

PRECLINICAL STUDY: Effects of aqueous, methanolic and chloroform extracts of rhizome and aerial parts of Valeriana officinalis L. on naloxone‐induced jumping in morphine‐dependent mice

In the present study, the effects of rhizomes and aerial parts extracts of Valeriana officinalis L. on morphine dependence in mice have been investigated. Animals were treated subcutaneously with morphine (50, 50 and 75 mg/kg) three times daily (10 am, 1 pm and 4 pm) for 3 days, and a last dose of morphine (50 mg/kg) was administered on the fourth day. Withdrawal syndrome (jumping) was precipitated by naloxone (5 mg/kg) which was administered intraperitoneally 2 hours after the last dose of morphine. To study the effects of the aqueous, methanolic and chloroform extracts of both aerial parts and rhizome of the V. officinalis L. on naloxone-induced jumping in morphine-dependent animals, 10 injections of morphine (three administrations each day) for dependence and a dose of 5 mg/kg of naloxone for withdrawal induction were employed. Intraperitoneal injection of different doses (1, 5, 25 and 50 mg/kg) of aqueous, methanolic and chloroform extracts of the rhizome of V. officinalis L. 60 minutes before naloxone injection decreased the jumping response dose-dependently. Pre-treatment of animals with different doses (1, 5, 25, 50 and 100 mg/kg) of aqueous and methanolic extracts of aerial parts of V. officinalis L. 60 minutes before naloxone injection caused a significant decrease on naloxone-induced jumping. The chloroform extract of the aerial parts of V. officinalis L. did not show any significant changes on jumping response in morphine-dependent animals. It is concluded that the extracts of V. officinalis L. could affect morphine withdrawal syndrome via possible interactions with inhibitory neurotransmitters in nervous system.

The Effects of Dopamine Receptor Agents on Swim Stress-Induced Inhibition of Naloxone-Induced Jumping Behavior in Morphine-Dependent Mice

In the present study, interactions of dopamine receptor agonists and antagonists with water swimming stress (WSS) on naloxone-induced jumping in morphine-dependent mice were examined. Mice were rendered dependent as described in the methods section. The opioid receptor antagonist, naloxone (1 mg/kg), was injected to elicit jumping (as a withdrawal sign). The first group exposed to WSS in the presence or absence of dopamine receptor drugs, before naloxone injection, in order to test the interaction of dopamine receptor mechanisms with WSS on expression of jumping behavior. When the animals were exposed to WSS for periods of 0.5, 1 or 3 min, 15 min prior to naloxone injection, WSS administration for a period of 3 min decreased the expression of jumping, but not diarrhea induced by naloxone. The D1 receptor agonist, SKF38393 (1-phenyl-7,8-dihydroxy-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride; 8 and 16 mg/kg), D1 receptor antagonist, SCH 23390 (R-(+)-8-chloro-2,3,4,5tetrahydro-3-methyl-5-phenyl-1Hbenzazepine=7-ol maleate; 0.0025 and 0.005 mg/kg), D2 receptor agonist, quinpirole (0.3 and 0.5 mg/kg) and D2 receptor antagonist, sulpiride (50 mg/kg), potentiated the inhibition of jumping induced by WSS. Quinpirole, but not other dopamine receptor agents, increased diarrhea. In the second group of animals, effects of the dopamine receptor drugs; during development of morphine dependence, in the presence of WSS administration were tested. Administration of apomorphine (1 and 2 mg/kg) or SKF 38393 (8 mg/kg) in the presence of WSS, during the development of morphine dependence increased jumping, while quinpirole (0.5 mg/kg) decreased diarrhea. In contrary, neither sulpiride nor SCH 23390 did not alter jumping or diarrhea induced by naloxone. It could be concluded that dopamine receptor mechanism(s) and/or WSS could be related the development of morphine dependency.

Naloxone-induced morphine withdrawal increases the number and degranulation of mast cells in the thalamus of the mouse

Naloxone-induced jumping in morphine-dependent mice is inhibited by cromolyn, a mast cell stabilizer, suggesting that this characteristic withdrawal behavior results from degranulation of mast cells. Because withdrawal is considered as a central phenomenon, degranulation of mast cells located within the CNS may influence aspects of opioid withdrawal. The present study evaluates histologically whether naloxone, injected into opioid dependent mice, induces degranulation of mast cells. Seventy-two hours after the s.c. implantation of a 75 mg morphine pellet, the number and degranulation of thalamic mast cells did not differ from those in placebo-implanted controls. However, two injections of 50 mg/kg of naloxone, 30 and 60 min before tissue collection, increased the number of degranulated mast cells compared to those in mice injected with saline. Analysis throughout the entire thalamus (90 40-μ sections) revealed increases in the total number of mast cells as well as the number that were degranulated, especially in sections 52–60, corresponding to Bregma −2.18 to 2.54. Here, mast cells were clustered in the IGL and VPL/VPM nuclei, and redistributed from the ventromedial to the dorsolateral aspects of the Po and PF nuclei during withdrawal. Degranulation was also greater throughout the LD, LP nuclei during withdrawal. These data reveal a novel neuroimmune reaction to opioid withdrawal in the CNS.

Effects of imipramine on the expression and development of morphine dependence in mice

In the present study, the effects of imipramine and/or α-adrenoceptor agents on naloxone-induced jumping in morphine-dependent mice were examined. In the first set of experiments, the drugs were used before naloxone injection, to test their effects on the expression of jumping. Administration of imipramine (10–60 mg/kg) 15 min before naloxone increased the number of jumping in mice. Injection of the α 2-adrenoceptor agonist, clonidine (0.1 mg/kg), or α 1-adrenoceptor agonist, phenylephrine (4 mg/kg), themselves neither altered naloxone-induced jumping nor influenced the imipramine response. The α 2-adrenoceptor antagonist, yohimbine (4 mg/kg), itself but not the α 1-adrenoceptor antagonist, prazosin (1 mg/kg), increased jumping and decreased the imipramine effect. In the second set of experiments, imipramine and/or the α-adrenoceptor drugs were injected during the development of morphine dependence. Imipramine (10–40 mg/kg) increased the development of dependence and increased jumping was seen. Clonidine did not influence the imipramine effect. Phenylephrine was lethal in combination with imipramine. Both yohimbine and prazosin decreased the effect of imipramine. Imipramine and phenylephrine but not clonidine, yohimbine or prazosin decreased locomotion. It is concluded an α 2-adrenoceptor mechanism may be involved in the influence of imipramine on the expression and development of naloxone-induced withdrawal signs in mice.

Influence of histamine, cimetidine and pyrilamine on naloxone-induced jumping in morphine-dependent mice

In the present study, the effects of histamine on naloxone-induced jumping in the presence or absence of adrenoceptor or acetylcholine receptor antagonists in morphine-dependent mice were examined. In these experiments, the drugs were used before s.c. injection of naloxone (2 mg/kg), to test their effects on the expression of jumping. The i.c.v. administration of histamine (5–20 μg/mouse) 15 min before naloxone injection decreased the number of jumps in mice. When the histamine H 2 receptor antagonist, cimetidine (5–20 mg/kg), and the histamine H 1 receptor antagonist, pyrilamine (5–20 mg/kg), were administered i.p. to morphine-dependent mice, only cimetidine enhanced the jumping behaviour. Administration of cimetidine (20 mg/kg, i.p.), 30 min, of the β-adrenoceptor antagonist, propranolol (2.5–10 mg/kg, i.p.), 15 min but not of pyrilamine (20 mg/kg, i.p.), 30 min before naloxone injection, decreased the histamine effect. The i.p. administration of an acetylcholine receptor antagonist, atropine (5 and 10 mg/kg, i.p.), the α 1-adrenoceptor antagonist, prazosin (0.5, 1 and 2 mg/kg, i.p.), and α 2-adrenoceptor antagonist, yohimbine (0.5, 1 and 2 mg/kg, i.p.), 15 min before naloxone injection, had no effect on the histamine response. Single administration of propranolol, atropine or prazosin decreased, while yohimbine increased the naloxone-induced jumping. It is concluded that the histamine H 2 receptor mechanism may be involved in the influence of histamine on the expression of naloxone-induced jumping in morphine-dependent mice.

The effects of dopamine receptor agents on naloxone-induced jumping behaviour in morphine-dependent mice

In the present study, the effects of dopamine receptor agonists and antagonists on naloxone-induced jumping in morphine-dependent mice were examined. Mice were rendered dependent as described in the methods section. Naloxone was injected to elicit jumping (as withdrawal sign). The first group received dopamine receptor drugs before naloxone injection to test the effects of the drugs on the expression of jumping. Administration of the dopamine D1/D2 receptor agonist, apomorphine (0.25, 0.5 and 1 mg/kg), decreased jumping, but not diarrhoea, induced by naloxone. The effect of apomorphine on jumping was reduced by the dopamine D2 receptor antagonist, sulpiride. The dopamine D2 receptor agonist, quinpirole (0.1, 0.3 and 0.5 mg/kg), increased jumping, while it decreased diarrhoea in mice. Different doses of sulpiride did not alter jumping, but one dose of the drug (12.5 mg/kg) decreased jumping. Neither the dopamine D1 receptor agonist, SKF38393 (1-phenyl-7,8-dihydroxy-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride; 8 and 16 mg/kg), nor the dopamine D1 receptor antagonist, SCH23390 (R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-benzazepine-7-ol maleate; 5, 10 and 25 mg/kg), altered jumping, but they decreased diarrhoea. The second group of animals received the drugs during the development of dependence. Administration of quinpirole (0.1, 0.3 and 0.5 mg/kg), but not bromocriptine (4, 8 and 16 mg/kg), apomorphine (0.25, 0.5, 1 and 2 mg/kg) or sulpiride (12.5, 25 and 50 mg/kg) decreased naloxone-induced jumping and diarrhoea. A dose of SKF38393 (8 mg/kg) decreased jumping, while both SKF38393 (4 and 16 mg/kg) and SCH23390 (5 and 10 μg/kg) increased diarrhoea. It is concluded that activation of both dopamine D1 and D2 receptors may suppress naloxone-induced jumping in morphine-dependent mice, and that stimulation of dopamine D1 receptors during development of morphine dependence may increase diarrhoea through peripheral mechanism.

Effects of GABAergic system on naloxone-induced jumping in morphine-dependent mice

The effect of GABA (γ-aminobutyric acid system) receptor agonists and antagonists on naloxone-induced jumping in morphine-dependent mice was examined. Intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) injection of different doses of the GABA B receptor agonist, baclofen (2.5, 5 and 10 mg/kg), reduced naloxone-induced jumping in morphine-dependent mice. The i.p. administration of the GABA B receptor antagonist, CGP35348 ( P-[3-aminopropyl]- p-diethoxymethyl-phosphinic acid), but not the i.c.v. injection of the drug, increased naloxone-induced jumping. The antagonist also decreased the baclofen response. Administration of the GABA A receptor agonist, muscimol, but not the GABA A receptor antagonists bicuculline and picrotoxin, decreased the naloxone response in morphine-dependent animals. It is concluded that both GABA A and GABA B receptor subtypes may have an inhibitory influence on naloxone-induced withdrawal jumping in mice.

On the mechanism(s) of cholecystokinin (CCK): receptor stimulation attenuates morphine dependence in mice.

In the present study, effect of cholecystokinin (CCK) agonists and on dependence to morphine in mice has been investigated. The influence of dopaminergic, adrenergic, cholinergic and serotonergic on attenuation of naloxone-induced jumping in morphine-dependent mice by CCK agonists were also considered. Mice were treated subcutaneously with morphine (50, 50 and 75 mg/kg) three times daily (10 a.m. 1 p.m. and 4 p.m.) for 3 days, and a last dose of morphine (50 mg/kg) was administered on the 4th day. Withdrawal syndrome (jumping) was precipitated by naloxone (5 mg/kg) which was administered intraperitoneally 2 hr after the last dose of morphine. To study effects of CCK receptor agonists, 10 injection of morphine (3 administrations each day) for dependence and a dose of 5 mg/kg of naloxone for withdrawal induction were employed. The CCK agonists CCK-8 (0.001-0.1 mg/kg), unsulfated CCK-8 (CCK-8U; 0.001-0.1 mg/kg) and caerulein (0.00001-0.01 mg/kg) were able to prevent withdrawal signs precipitated by naloxone (5 mg/kg). Sulpiride and pimozide increased response induced by CCK-8 agonists. The dopamine antagonists also attenuates jumping by themselves. SCH 23390 did not alter the CCK-8 effect, but decreased the jumping by itself. Phenoxybenzamine, propranolol, methysergide and atropine did not change the caerulein effect significantly. However, single administration of atropine increased and methysergide decreased jumping. It is concluded that CCK mechanism(s) may be involved in morphine dependence, and dopaminergic mechanism(s) may interact with CCK in attenuation of naloxone-induced jumping.