Article

Guanosine Prevents Thermal Hyperalgesia in a Rat Model of Peripheral Mononeuropathy

Graduate Program in Biochemistry, Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
The journal of pain: official journal of the American Pain Society (Impact Factor: 4.01). 10/2009; 11(2):131-41. DOI: 10.1016/j.jpain.2009.06.010
Source: PubMed

ABSTRACT

It is well known that adenine-based purines exert multiple effects on pain transmission. Less attention has been given, however, to the antinociceptive effects of guanine-based purines. The aim of this study was to investigate the effects of intraperitoneal administration of guanosine on a rat model of peripheral mononeuropathy. Additionally, investigation of the mechanism of action of guanosine, its general toxicity and measurements of central nervous system purine levels were performed. Rats received an intraperitoneal administration of vehicle (0.1 mM NaOH) or guanosine (up to 120 mg.kg(-1)) in an acute or chronic regimen. Guanosine significantly reduced thermal hyperalgesia on the ipsilateral side of the sciatic nerve ligation. Additionally, guanosine prevented locomotor deficits and body weight loss induced by the mononeuropathy. Acute systemic administration of guanosine caused an approximately 11-fold increase on central nervous system guanosine levels, but this effect was not observed after chronic treatment. Chronic guanosine administration prevented the increase on cortical glutamate uptake but not the decrease in spinal cord glutamate uptake induced by the mononeuropathy. No significant general toxicity was observed after chronic exposure to guanosine. This study provides new evidence on the mechanism of action of guanine-based purines, with guanosine presenting antinociceptive effects against a chronic pain model. PERSPECTIVE: This study provides a new role for guanosine: chronic pain modulation. Guanosine presents as a new target for future drug development and might be useful for treatment of neuropathic pain.

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Available from: Elaine Elisabetsky, Oct 15, 2015
    • "Certainly, GUO effects seem to be directly mediated by action on the brain, as intracerebroventricular or intracortical GUO infusion in experimental models of excitotoxicity have demonstrated neuroprotection[8,13]. Nevertheless, most of the neuroprotective effects exerted by GUO were observed after its systemic (intraperitoneal[IP]or oral) administration[7,910111213141516. In this regard, systemic administration routes present important limitations for protocols with endogenous drugs that aim to reach the brain but can be metabolized in the systemic pathway, which is the case for GUO. "
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    • "Guo and Urd. Our results imply that Guo, Urd and their analogs may be useful, effective and safe antiepileptic drugs (Lara et al., 2001; Kimura et al., 2001b; Kova´cs and Dobolyi, 2013; Kova´cs et al., 2014) in the treatment of human absence epilepsy because Guo and Urd are well tolerated drugs with only minor toxic potential as demonstrated previously (Lara et al., 2001; Vinadeét al., 2003; Zhao et al., 2008; Schmidt et al., 2010). "
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