Blockade of Tolerance to Morphine but Not to Opioids by a Nitric Oxide Synthase Inhibitor (Nitric Oxide/Opiate/Dependence/Naloxone Benzoylhydrazone/U50,488H)
Total Page：16
File Type：pdf, Size：1020Kb
Proc. Natl. Acad. Sci. USA Vol. 90, pp. 5162-5166, June 1993 Pharmacology Blockade of tolerance to morphine but not to opioids by a nitric oxide synthase inhibitor (nitric oxide/opiate/dependence/naloxone benzoylhydrazone/U50,488H) YURI A. KOLESNIKOV, CHAIM G. PICK, GRAZYNA CISZEWSKA, AND GAVRIL W. PASTERNAK The Cotzias Laboratory of Neuro-Oncology, Memorial Sloan-Kettering Cancer Center, Departments of Neurology and Neuroscience and Pharmacology, Cornell University Medical College, New York, NY 10021 Communicated by Paul A. Marks, February 2, 1993 (received for review December 3, 1992) ABSTRACT The nitric oxide synthase inhibitor NG-nitro- the NOS inhibitor NO2Arg on the development of tolerance L-arginine (NO2Arg) blocks morphine tolerance in mice. After to morphine and extended these studies to K1 (trans-3,4- implantation of morphine pellets the analgesic response de- dichloro-N-methyl-N-[2-(1-pyrrolindinyl)cyclohexyl]-ben- creases from 100% on the first day to 0% on the third. zeneacetamide; U50,488H) and K3 [naloxone benzoylhydra- Coadministration of NO2Arg along with the pellets markedly zone (NalBzoH)] analgesics. retards the development of tolerance; 60% of mice are anal- gesic after 3 days, and 50% of mice are analgesic after 5 days. In a daily injection paradigm the analgesic response to mor- MATERIALS AND METHODS phine is reduced from 60% to 0% by 5 days. Concomitant Male CD-1 mice (25-35 g; Charles River Breeding Labora- administration of morphine along with NO2Arg at doses of 2 tories) were used in all studies. Morphine sulfate was ob- mg/kg per day prevents tolerance for 4 weeks. A single tained from Mallinckrodt, and U50,488H was from Upjohn. NO2Arg dose retards morphine tolerance for several days, and NalBzoH was synthesized as previously noted (2), and dosing every 4 days is almost as effective as daily NO2Arg. NO2Arg was purchased from Sigma. NalBzoH was dissolved NO2Arg slowly reverses preexisting tolerance over 5 days in 30% ethanol, which did not produce analgesia in control despite the continued administration of morphine along with mice, and doses are reported as the free base. All other drugs NO2Arg. NO2Arg also reduces dependence and reverses pre- were dissolved in saline. viously established dependence. NO2Arg does not prevent Analgesia was determined by using the radiant heat tail- tolerance to analgesia mediated by the Kc agonist trans-3,4- flick technique (1, 2, 16, 28, 29). After determining baseline dichloro-N-methyl-N-[2-(1-pyrrolindinyl)cyclohexyl]-benzene- latencies, post-treatment tail-flick latencies were determined acetamide (U50,488H) or the K3 agent naloxone benzoylhydra- at 30 min after the opioid, and a maximal latency of10 sec was zone, indicating a selective action of NO in the mechanisms of used to minimize tissue damage. Analgesia was defined as a ,u tolerance and dependence. doubling or greater of baseline values for each mouse. All analgesic values represent at least 10 mice. Extended dura- Chronic use of opioid analgesics invariably leads to toler- tion studies used several groups of at least 10 mice to avoid ance, but the lack of cross tolerance among ,u, K1, and K3 testing animals on >6 days. Dose-response curves were analgesics strongly suggests different mechanisms for the analyzed by using a modification of the BLISS version 20 subtypes (1, 2). Although tolerance may be seen at the level computer program (30), and ED50 values are given with 95% of the receptor and its second-messenger system (3-11), confidence limits. Single-dose comparisons used the Fisher some evidence suggests that morphine tolerance is mediated, exact test. Mean arterial blood pressure was assessed in in part, through activation of antagonistic systems and/or a halothane-anesthetized mice with carotid cannulae con- down-regulation of facilatory ones (12-17). However, chole- nected to a pressure transducer/blood pressure analyzer cystokinin antagonists and antidepressants active against (MicroMed, Louisville, KY). tolerance also potentiate morphine analgesia in naive animals as well, indicating that their actions are not directed specif- ically against tolerance. RESULTS N-methyl-D-aspartate (NMDA) mechanisms have been NO2Arg Actions on Morphine Tolerance. Subcutaneous associated with nociceptive neurons within the spinal cord implantation of a morphine pellet (75 mg of free base) and in the brainstem, and interactions between NMDA produces tolerance (4, 8). All mice are analgesic on the first receptors and opioids have been reported (18-23). Further- day (Fig. 1); the response rapidly drops to no analgesic more, the NMDA antagonists such as MK-801 (11) and the animals by the third day. NO2Arg (4 mg/kg per day) signif- competitive antagonist LY274614 block morphine tolerance icantly reduces the development of tolerance; 50% of the and even aspects of dependence (23). Recent work has mice are analgesic after 5 days. NO2Arg itselfis not analgesic established that many glutamate actions mediated through in this model, and neither acute nor chronic dosing with NMDA receptors result from the subsequent activation of NO2Arg significantly influences the analgesic potency of nitric oxide synthase and the formation of NO (24-26). A morphine in opiate-naive animals (Table 1). brief report indicated that inhibition of nitric oxide synthase We also used a daily injection paradigm that is not depen- (NOS) interfered with the development of dependence (27), dent upon the availability of pellets and, thus, can be ex- and we recently reported the ability of a relatively high dose tended to a wide variety of opioids. Single daily injections of of NG-nitro-L-arginine (NO2Arg) to prevent tolerance to morphine (5 mg/kg) significantly increase the ED50 value of morphine (28). To explore further the role of NO in opioid morphine 2-fold after 5 days, 4-fold by 10 days, and 8-fold by tolerance we have examined the effects of several doses of Abbreviations: NOS, nitric oxide synthase; NO2Arg, NG-nitro-L- The publication costs of this article were defrayed in part by page charge arginine; U50,488H, trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolin- payment. This article must therefore be hereby marked "advertisement" dinyl)cyclohexyl]-benzeneacetamide; NalBzoH, naloxone benzoyl- in accordance with 18 U.S.C. §1734 solely to indicate this fact. hydrazone; NMDA, N-methyl-D-aspartate. 5162 Downloaded by guest on September 28, 2021 Pharmacology: Kolesnikov et al. Proc. Natl. Acad. Sci. USA 90 (1993) 5163 1 OCi Pellets alone M 75 Pellets + NOArg 0 o-0 50 Ak eCO a) - -- Morphine 25-\ - ---- + NO.Arg 1 mg/kg/d -0- + NO2Arg 2 mg/kg/d 0 1 2 3 4 5 Days Days FIG. 1. Effect of NO2Arg on tolerance to morphine pellets. One group of mice received morphine pellets (75 mg of free base) on day B 100 1 and was tested for analgesia on days 1 (n = 10), 2 (n = 10), and 3 (n = 9). Another group (n = 10) received NO2Arg (4 mg/kg i.p.) on day 0 after which the mice continued to receive daily NO2Arg (4 A A mg/kg i.p.) injections. They received their morphine pellets (75 mg E" 75- of free base) on day 1 and were tested for analgesia on days 1-5. E co 28 days (Table 1). The analgesic response to fixed, daily 0 X Morphine (10 mg/kg) morphine injections decreases from 60% to 0% over 5 days X0 50 A (Fig. 2A). Coadministration of NO2Arg along with morphine .i \+ NOArg (2 mg/kg) prevents this tolerance in a dose-dependent manner. A daily dose of 2 mg/kg per day maintains the analgesic response to 25- a fixed morphine dose for >4 weeks and prevents any significant change in the ED50 value of morphine in the co The lower NO2Arg group after 5 or 10 days (Table 1). NO2Arg 0 dose (1 mg/kg per day) is only partially effective (Fig. 2A). 1 4 7 10 NO2Arg also works against a higher morphine dose (10 Days mg/kg; Fig. 2B). To avoid using supramaximal doses, all dose. FIG. 2. Effect of NO2Arg on tolerance to daily morphine injec- remaining studies used the lower (5 mg/kg) tions. (A) Animals received morphine (5 mg/kg s.c.) alone (o) or with The actions of NO2Arg can be very long lasting (Fig. 3), NO2Arg (i.p.) at doses of 2 mg/kg per day (n = 20; 1 mg/kg at times perhaps due to its ability to irreversibly inhibit NOS (31). A -15 min and 1 hr each day; *) or 1 mg/kg per day (n = 10; 1 mg/kg at -15 min; A). Analgesia was assessed 30 min after opioid admin- Table 1. Effect of acute and chronic morphine and NO2Arg on istration (time 0). Baseline latencies were determined each day for morphine analgesia each mouse before any drug injections and did not vary significantly Morphine, 95% confidence over the days of testing. All points represent at least 10 mice. At 5 Treatment ED50 in mg/kg limits days, the morphine-alone group differed significantly from the 1 mg/kg per day dose (P < 0.05) and from the 2 mg/kg per day dose Morphine alone on day 7 (P < 0.02). (B) Groups of mice (n = 20) received morphine Day 1 4.4 3.6, 5.3 (10 mg/kg s.c.) alone (o) or with daily NO2Arg (v) (2 mg/kg per day Day 5 8.8 6.2, 11.3 i.p.) given 15 min before morphine. Analgesia was assessed as Day 10 17.2 11.8, 23.8 described above. At day 10, the NO2Arg differed significantly (P < Day 28 37.8 26.6, 51.1 0.001) from the morphine-alone group. NO2Arg alone single dose ofNO2Arg retards the appearance oftolerance for Day 1 several days, and NO2Arg given every 4 days maintains the 1 mg/kg 4.6 3.1, 6.7 as well as 2 mg/kg 3.9 2.8, 5.4 analgesic potency ofmorphine approximately daily Day 10 NO2Arg (Fig.