Geisson Marcos Nardi

Publications (2)5.63 Total impact

• Article: Opioid analgesics in experimental sepsis: effects on physiological, biochemical, and haemodynamic parameters.

  Geisson Marcos Nardi, Angela Cristina Bet, Regina Sordi, Daniel Fernandes, Jamil Assreuy
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  ABSTRACT: Cecal ligation and puncture (CLP) is the sepsis model that more closely resembles the human pathology, but it is likely to cause suffering to experimental animals. However, it is not clear whether the use of analgesia may affect some parameters evaluated in experimental sepsis research. Therefore, we investigated the effects of fentanyl and tramadol in experimental sepsis in the rat. The following parameters were evaluated: body temperature, body weight, water and food ingestion, mortality, analgesia, blood leukocytes, mean arterial blood pressure, vascular reactivity to phenylephrine, lung myeloperoxidase activity, and plasma levels of IL1-β, glutamic-oxaloacetic, glutamic-pyruvic, lactate, creatinine and urea. While producing significant analgesia, the opioids modify minimally the parameters, with the exception of sepsis-induced hypotension and mortality. Although fentanyl and tramadol can minimize pain and the general suffering of animals submitted to CLP surgery, their effects on cardiovascular parameters as well as in the mortality indicate that their use in experimental sepsis must be done with caution and with all the proper control groups.
  Fundamental and Clinical Pharmacology 04/2012; · 1.80 Impact Factor
• Article: Late, but not early, inhibition of soluble guanylate cyclase decreases mortality in a rat sepsis model.

  Daniel Fernandes, Regina Sordi, Letícia Kramer Pacheco, Geisson Marcos Nardi, Bettina Tomio Heckert, Christina Gaspar Villela, Amanda Revoredo Lobo, Christina Barja-Fidalgo, Jamil Assreuy
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  ABSTRACT: Overproduction of nitric oxide and activation of soluble guanylate cyclase (sGC) are important in sepsis-induced hypotension and hyporesponsiveness to vasoconstrictors. A time course of the expression and activity of sGC in a sepsis model [cecal ligation and puncture (CLP)] was evaluated in rats. Soluble GC alpha-1 and beta-1 subunit mRNA levels increased in the lungs, but not in the aorta. However, in both tissues, the protein levels increased 24 h after sepsis and remained high for up to 48 h. Sodium nitroprusside-stimulated cGMP accumulation was higher 48 h after CLP in the lung and aorta. NOS-2 protein expression peaked 24 h after CLP, decreasing thereafter. The impact of inhibiting the expression of sGC early (8 h) or late (20 h) on vascular reactivity and the indexes of organ damage and mortality were also studied. Late administration of methylene blue (MB) or ODQ (1H-[1,2,4]-oxadiazole[4,3-a]quinoxalin-1-one) restored the blood pressure and vascular responsiveness to vasoconstrictors to normal levels but was ineffective in early sepsis. Late MB injection reduced the plasma levels of urea, creatinine, and lactate. MB improved the survival if administered late, but it increased the mortality when administrated early after sepsis onset. The increased sGC expression/activity may be relevant for the late hypotension and hyporesponsiveness to vasoconstrictors in sepsis. In accordance, MB increased survival if administered in late sepsis, but not in early sepsis. Therefore, differential responsiveness to sGC during the course of sepsis may determine the success or failure of treatment with sGC inhibitors.
  Journal of Pharmacology and Experimental Therapeutics 01/2009; 328(3):991-9. · 3.83 Impact Factor