Morphine Withdrawal Signs In Rats Research Articles

The adenosinergic system is involved in sensitization to morphine withdrawal signs in rats-neurochemical and molecular basis in dopaminergic system.

RationaleExperimental data informs that not only do the dose and time duration of dependent drugs affect the severity of withdrawal episodes. Previous withdrawal experiences may intensify this process, which is referred as sensitization to withdrawal signs. Adenosine and dopamine (DA) receptors may be involved in this sensitization.ObjectivesRats were continuously and sporadically treated with increasing doses of morphine for 8 days. In rats, sporadically treated with morphine, morphine administration was modified by adding three morphine-free periods. Adenosine agonists were given during each of the morphine-free periods (six injections in total). On the 9th day, morphine was injected. One hour later, naloxone was administered to induce morphine withdrawal signs. Then, the animals were placed into cylinders and the number of jumpings was recorded. Next, the rats were decapitated and brain and brain structures (striatum, hippocampus, and prefrontal cortex) were dissected for neurochemical, molecular, and immunohistochemical experiments within DAergic pathways.ResultsWe demonstrated that previous experiences of opioid withdrawal intensified subsequent withdrawal signs. Adenosine ligands attenuated the sensitization to withdrawal signs. In a neurochemical study, the release of DA and its metabolites was impaired in all structures. Significant alterations were also observed in mRNA and protein expression of DA receptors.ConclusionsResults demonstrate that intermittent treatment with morphine induces alterations in the DAergic system which may be responsible for sensitization to morphine withdrawal signs. Although adenosine ligands attenuate this type of sensitization, they are not able to fully restore the physiological brain status.

The blockade of GABAA receptors attenuates the inhibitory effect of orexin type 1 receptors antagonist on morphine withdrawal syndrome in rats

The aim of present study was to investigate the involvement of orexin-A neuropeptide in naloxone-induced morphine withdrawal syndrome via modulating neurons bearing GABAA receptors. The locus coeruleus (LC) is a sensitive site for expression of the somatic aspects of morphine withdrawal. Intra-LC microinjection of GABAA receptor agonist attenuates morphine withdrawal signs in rats. Here we studied the influence of LC orexin type 1 receptors blockade by SB-334867 in presence of bicuculline, a GABAA receptor antagonist, on naloxone-induced morphine withdrawal syndrome.Adult male Wistar rats, weighing 250–300g, were rendered dependent on morphine by subcutaneous (s.c.) injection of increasing morphine doses (6, 16, 26, 36, 46, 56 and 66mg/kg, 2ml/kg) at set intervals of 24h for 7 days. On 8th day, naloxone (3mg/kg, s.c.) was injected and the somatic signs of morphine withdrawal were evaluated. Intra-LC microinjections (0.2μl) of either bicuculline (15μM) or SB-334867 (3mM) or a combination of both chemicals were done immediately before naloxone injection. Intra-LC microinjection of bicuculline (15μM) had no significant effect on morphine withdrawal signs, whereas intra-LC microinjection of SB-334867 considerably attenuated morphine withdrawal signs. However, the effect of SB-334867 in attenuating naloxone-induced morphine withdrawal signs was blocked in presence of bicuculline. This finding, for the first time, indicated that orexin-A may participate in expression of naloxone-induced morphine withdrawal syndrome partly through decreasing the activity of neurons bearing GABAA receptors.

Dendrosomal Curcumin Nanoformulation Attenuates Naloxone Precipitated Morphine Withdrawal Signs in Rats

Curcuminis known to possess a wide range of therapeutic and pharmacological properties as anti-inflammatory, antitumor, antinociceptive and neuroprotective agents. The recent achievements of nanotechnology illustrate a novel approach in treatment of drug abuse and addiction. Curcumin as a new candidate can be exploited for drug abuse treatment, but its low bioavailability and water solubility is the most important obstacles and limits its application. Here, curcumin was efficiently encapsulated in a nontoxic nanocarrier, labeled dendrosome, to overcome these problems. The present study is designed to investigate the effect of intraperitoneal (i.p.) administration of Dendrosomal curcumin (DNC) on the behavioral signs of morphine withdrawal syndrome. Male Wistar rats weighing 250-300 g were rendered dependent on morphine by subcutaneous (s.c.) administration of morphine sulfate (6, 16, 26, 36, 46, 56 and 66 mg/kg, 2 ml/kg) at set intervals of 24 h for 7 days. The animals received i.p. administration of DNC(12.5 mg/kg) immediately after each morphine injection. On day 8, naloxone (2 mg/ kg, i.p.) was injected and behavioral signs of morphine withdrawal were assessed for 25 min. Our results show that i.p. injection of DNC significantly decreases naloxone precipitated morphine withdrawal signs. The present study indicates that intraperitoneal administration of Dendrosomal curcumin exerts a significant effect on morphine dependency in rats.

P.6.c.010 The efffect of agmatine in nucleus accumbens on morphine withdrawal signs in rats

P.6.c.010 The efffect of agmatine in nucleus accumbens on morphine withdrawal signs in rats

P.6.c.011 The effect of GABA agonists in nucleus accumbens on morphine withdrawal signs in rats

The brain and the placenta synthesize identical peptides and proteins, such as brain-derived neurotrophic factor, oxytocin, vascular endothelial growth factor, cortisol, and matrix metalloproteinases. Given the promiscuity between neurochemistry and the mechanism of placentation, it would be expected that mental disorders occurring during pregnancy would increase the risk of adverse obstetric and neonatal outcomes. Indeed, expectant mothers with anxiety disorders, post-traumatic stress disorder, schizophrenia, or depressive disorders are at higher risk of preterm birth, low-birth-weight and small-for-gestational-age infants than controls. These mental illnesses are accompanied by a procoagulant phenotype and low activity of tissue plasminogen activator, which may contribute to placental insufficiency. Another risk factor for pregnancy complications is hyperemesis gravidarum, more common among women with eating disorders or anxiety disorders than in controls. Severe hyperemesis gravidarum is associated with dehydration, electrolyte imbalance and malnutrition, all of which may increase the risk of miscarriages, of low-birth-weight babies and preterm birth. This paper reviews some aspects of mental disorders that may influence pregnancy and neonatal outcomes.

Examining the effect of the CaMKII inhibitor administration in the locus coeruleus on the naloxone-precipitated morphine withdrawal signs in rats

Drug addiction is an occurrence with physiological, psychological, and social outcomes. Repeated drug exposure causes neuronal adaptations and dependency. It has been shown that CaMKIIα enzyme contributes to morphine dependency. The locus coeruleus nucleus has been implied in the morphine withdrawal syndrome. This research focuses on the behavioral and molecular adaptations that occur in the locus coeruleus neurons in response to the chronic morphine exposure. Adult male Wistar rats were injected by morphine sulfate (10 mg/kg/s.c.) at an interval of 12 h for a period of nine subsequent days. On the tenth day, naloxone (1 mg/kg/i.p.) was injected 2 h after the morphine administration. Somatic withdrawal signs were investigated for 30 min. We concluded that the inhibition of CaMKIIα by administration of KN-93, the specific inhibitor of this enzyme, significantly attenuated some of the withdrawal signs. In molecular method, the expression of CaMKIIα protein has been enhanced in locus coeruleus of the morphine dependent rats. These findings indicate that CaMKIIα may be involved in the modulation of the naloxone-induced withdrawal syndrome, and treatment with KN-93 may have some effects on this system.

The Effects of Angiotensin II and Captopril on Expression of Morphine Withdrawal Signs in Rat

The mechanisms of drug dependence and rewarding properties of opiates are not exactly known and several neurotransmitters seem to be involved. It is possible that the rennin-angiotensin system could interact with the opioid system, since it has been shown that angiotensin II(Ang) and ACE inhibitors have analgesic, anticonvulsant and antidepression effects and in some cases they could antagonize the effect of morphine. In the present study, the effect of Ang II and captopril on withdrawal signs was evaluated. Male wistar rats were anesthetized and i.c.v cannula implanted and allowed to recover from surgery. Morphine was injected (i.p, 3 times a day) for 4 days to induce morphine dependence. The animals were divided into 3 groups and received saline, captopril, Ang II, and i.c.v, before naloxone injection. Naloxone precipitated morphine withdrawal signs, compared to the morphine dependent rats in saline, captopril and Ang II groups. Results showed that in the captopril group, some of the withdrawal signs were significantly lower than the saline group (p<0.05 and p<0.01). In the Ang II group, some of the withdrawal signs were greater than the saline group (p<0.01 and p<0.001). Considering the fact that captopril can reduce endogenous opioid degradation, it could probably reduce the morphine withdrawal signs in this way. On the other hand, captopril and Ang II can interact with dopamine, serotonin, substance p, acetylcholine or nitric oxide in different brain regions and alter morphine withdrawal signs.

Antagonism of orexin type 1 receptors in the locus coeruleus attenuates signs of naloxone-precipitated morphine withdrawal in rats

It has been shown that orexin neuropeptides contribute to morphine-induced physical dependence. The locus coeruleus (LC), which receives a dense extra-hypothalamic orexinergic projection, is a key brain region implicated in the expression of somatic signs of morphine withdrawal syndrome. The aim of the present study is to investigate the role of LC orexin type 1 receptors (OXR1) on naloxone-precipitated morphine withdrawal signs in rats. Adult male Wistar rats were rendered dependent on morphine by subcutaneous (s.c.) injection of morphine sulfate (10 mg/kg) at an interval of 12 h for 9 days. On day 10, naloxone (1 mg/kg i.p.) was injected 2 h after morphine administration. Somatic signs of withdrawal were then evaluated in a clear Plexiglas test chamber (30 cm diameter, 50 cm height) for 25 min. One group of animals received intra-LC SB-334867-A, a selective OXR1 antagonist, (100 μM, 0.2 μl) immediately before naloxone. In the control group, SB-334867-A vehicle was microinjected into the LC in the same manner. The results showed that intra-LC OXR1 receptor blockade significantly decreased the somatic signs of withdrawal including chewing, diarrhea, scratching, teeth chattering, wet-dog shake and ptosis. These results suggest that activation of OXR1 in the LC might be involved in the expression of withdrawal signs in morphine dependent rats.

Angiotensin converting enzyme inhibitor captopril modifies conditioned place preference induced by morphine and morphine withdrawal signs in rats

Angiotensin II and angiotensin converting enzyme (ACE) inhibitors have analgesic, anticonvulsant and antidepressive effects and in some cases they can antagonize morphine. In the present study effects of angiotensin II and ACE inhibitor captopril administered intracerobroventricularily (icv) on conditioned place preference induced by morphine as well as on morphine withdrawal signs has been evaluated in rats. Icv canullas were implanted in anesthetized male rats. Rats were allowed to recover from the surgery and conditioned place preference was induced by morphine, and the time spent in morphine compartment was compared in saline, morphine, captopril and Ang II groups. Morphine withdrawal signs were compared in three other groups of rats: morphine alone, captopril + morphine and Ang II + morphine 4 days after morphine injections (three times in each day) with naloxone injection on 4th day. Results with rats conditioned place preference induced by morphine showed that icv captopril decreased significantly the time in morphine compartment ( P < 0.01) while Ang II had no effect. In morphine dependent rats captopril decreased some withdrawal signs after naloxone precipitation ( P < 0.05 and P < 0.01). Ang II administration augmented some of withdrawal signs than in the morphine group ( P < 0.01 and P < 0.001). In conclusion captopril reduced conditioned place preference induced by morphine and some withdrawal signs in morphine dependent rats.

Influence of nociceptin(1-17) fragments and its tyrosine-substituted derivative on morphine-withdrawal signs in rats.

Our previous studies demonstrated that endogenous ligand of nociceptin (NOP) receptor, nociceptin(1-17) (also known as orphanin FQ), inhibits morphine-withdrawal syndrome measured as wet dog shakes in rats [Life Sci. 66 (2000) PL119]. This peptide is metabolized in the spinal cord, both in vitro and in vivo, to shorter fragments, including nociceptin(1-11) and nociceptin(1-6). These fragments, formed after cleavage by endogenous peptidase, are behaviorally active and modulate nociception in a bi-phasic process [Peptides 20 (1999) 239]. As these peptides induced transient naloxone-reversible analgesia in behavioral tests [Peptides 20 (1999) 239], in the present study we tested the influence of nociceptin(1-11) (10 and 20 microg) and nociceptin(1-6) (10, 20 and 40 microg) on the morphine-withdrawal syndrome in rats. Furthermore, the modified fragment of nociceptin(1-6) with an opioid-message domain achieved by replacement of Phe1 with Tyr was tested. Morphine-withdrawal syndrome was precipitated by the i.p. injection of naloxone hydrochloride (2 mg/kg), 72 h after implantation of morphine pellets. The wet-dog shakes were chosen for statistical analyses of the abstinence signs. The results show that nociceptin(1-11) and (1-6) attenuate this morphine-withdrawal symptom. The replacement of Phe1 with Tyr in nociceptin(1-6) fragment did not potentiate the influence of nociceptin(1-6) on wet dog shakes precipitated by naloxone in morphine-dependent rats.

ICV administration of CRF blocker (CRF 9–41 ∂ helical) reduces morphine withdrawal in rats

1. 1. The effects of CRF 9–41 ∂ helical on morphine withdrawal signs in rats were studied 2. 2. Intracerebroventricular administration of CRF 9–41 ∂ helical 5 at 10 μg/kg reduced central and peripheral symptons of the withdrawal syndrome, such as ptosis, jumping, wet dog shakes and teeth chatering; other signs remained unchanged. The effect were not dose dependent. 3. 3. The hypothermi characteristic of the Withdrawal sindrome was reduced by CRF 9–41 ∂ helical. 4. 4. These results suggest that the hypothalamo pituitary adrenal(HPA) axis play an important role in the morphine withdrawal syndrome in rats.

RP 67580, a selective antagonist of neurokinin-1 receptors, modifies some of the naloxone-precipitated morphine withdrawal signs in rats

In order to clarify the participation of substance P in the expression of opiate withdrawal, we have investigated the effects induced by the new selective neurokinin-1 antagonist RP 67580 on naloxone-induced morphine withdrawal syndrome in rats. Intracerebroventricular administration of RP 67580 elicited a decrease in 7 of the 13 withdrawal signs evaluated. Mastication, salivation and signs related to the motor component of withdrawal (jumping, rearing and locomotor activity) were particularly reduced. One sign, wet dog shakes, was increased, but it was also enhanced by the inactive enantiomer RP 68651. Our results indicate that blockade of NK1 receptors induces a decrease in the expression of naloxone-precipitated morphine abstinence in rats, and support the participation of substance P in the opiate withdrawal response.