Opioid receptor agonists are effective for treating pain; however, tolerance and dependence can develop with repeated use. Combining opioids with cannabinoids can enhance their analgesic potency, although it is less clear whether combined treatment alters opioid tolerance and dependence. In this study, four monkeys received 3.2 mg/kg morphine alone or in combination with 1 mg/kg Δ(9)-tetrahydro...

BACKGROUND Chronic administration of morphine cause physical dependence but the exact mechanism of this phenomenon remains unclear. The aim of this study is the assessment of systemic and intracerebroventricular (icv) administration of ramelteon (a melatonin receptor agonist) on morphine physical dependence. METHODS 88 adult male rats were divided into 2 major groups, namely "systematic" and ...

Preventing and reversing opioid dependence continues to be a clinical challenge and underlying mechanisms of opioid actions remain elusive. We report that matrix metalloproteinase-9 (MMP-9) in the spinal cord contributes to development of physical dependence on morphine. Chronic morphine exposure and naloxone-precipitated withdrawal increase activity of spinal MMP-9. Spinal inhibition or target...

The capacity of morphine to suppress natural and precipitated withdrawal was compared in morphine-dependent rhesus monkeys. A similar severity of withdrawal was induced by 14-hr deprivation or precipitated by naloxone, naltrexone, cyclazocine, Win 44,441 or MR 2266. Regardless of the procedure used to induce withdrawal, behavioral signs were completely suppressed by a cumulative dose of 17.5 mg...

To explore the effect of sinomenine on the nitric oxide (NO)/neural nitric oxide synthase (nNOS) system in the cerebellum and spinal cord of morphine-dependent and morphine-withdrawal Kunming mice, mice were subjected to injection of morphine with an increasing dose for 5 d, and then were treated with sinomenine (40 mg/kg, i.p.) for another 5 d. Naloxone was used to develop acute withdrawal, an...

Aloe vera is a herbal medicine for skin therapeutical objects. Many products like pomade, cream, gel, and shampoo for skin injuries have been made from this plant. Sometimes, the powder of this plant has also been used by mothers to keep out their infants from breast-feeding. In some of the books, this plant has been introduced as an opioid–receptors antagonist. In this study, 30 male mice (45-...

Effect of Otostegia persica on naloxone-induced morphine withdrawal syndrome was studied in male mice. Dependence was induced using daily subcutaneous injections of morphine for three days. Morphine was injected to mice at doses of 30 and 45mg/kg on day 1 and 60 and 90mg/kg on day 2 (8:00 am and 6:00 pm). On day 3, morphine (90mg/kg) was injected 1h before oral administration and 1.5h before in...

background and objective: regarding inefficiency of common drugs used for alleviation of anxiety due to narcotics withdrawal, the present study was evaluated methadone and haloperidol co-drugs therapy on anxiety due to morphine withdrawal. materials and methods: ninety eight nmri male mice were divided into acute and chronic experimental groups. then, each group was divided into 7 subgroups: sa...

The mixed agonist-antagonist analgesics buprenorphine, butorphanol, nalbuphine, pentazocine and picenadol were compared to the prototype mu and kappa agonists morphine and Mr 2033, respectively, in the following tests in rhesus monkeys: overt behavioral effects upon acute administration in drug-naive animals; discriminative stimulus properties in monkeys trained to respond to either etorphine o...