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Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 355, Issue 4, pp 447–451 | Cite as

Inhibition of nitric oxide synthesis accelerates the recovery of polysynapitc reflex potentials after transient spinal cord ischemia in cats

  • Tetsuharu Nemoto
  • Toshihiko Sekikawa
  • Toshio Suzuki
  • Hideshige Moriya
  • H. Nakaya
ORIGINAL ARTICLE

Abstract

Nitric Oxide (NO) has been implicated as a mediator of neuronal injury in vascular stroke. On the other hand, NO is suggested to play a neuroprotective role by increasing blood flow during cerebral ischemia. In order to evaluate the role of NO in the spinal cord ischemia, effects of nitric oxide synthase (NOS) inhibition on the recovery of reflex potentials after a transient spinal cord ischemia were examined in urethane-chloralose anesthetized spinal cats. Spinal cord ischemia was produced by occlusion of the thoracic aorta and the both internal mammary arteries for 10min. Regional blood flow (RBF) in the spinal cord was continuously measured with a laser-Doppler flow meter. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials elicited by electrical stimulation of the tibial nerve, were recorded from the L7 or S1 ventral root. The recovery process of spinal reflex potentials was reproducible when the oclusion was repeated twice at an interval of 120min. Pretreatment with N G-monomethyl-l-arginine (l-NMMA, 10mg/kg), a NOS inhibitor significantly accelerated the recovery of PSR potentials after spinal cord ischemia. The accelerating effect of l-NMMA on the recovery of PSR potentials was abolished by co-administration of l-arginine (1mg/kg/min) but not by that of d-arginine (1mg/kg/min). l-NMMA failed to improve RBF in the spinal cord during ischemia and reperfusion. Nitroprusside (10μg/kg/min), a NO donor, retarded the recovery of PSR potentials after spinal cord ischemia. These results suggest that NO production has a significant influence on the functional recovery after transient spinal cord ischemia.

Key words Nitric oxide NG-Monomethyl-l-arginine Nitroprusside Spinal cord Ischemia Reflex potential 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Tetsuharu Nemoto
    • 1
  • Toshihiko Sekikawa
    • 1
  • Toshio Suzuki
    • 1
  • Hideshige Moriya
    • 1
  • H. Nakaya
    • 1
  1. 1.Departments of Pharmacology and Orthopaedic Surgery, Chiba University School of Medicine, Chiba 260, JapanJP

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