NADPH-diaphorase reactivity and Fos-immunoreactivity within the ventral horn of the lumbar spinal cord of cats submitted to acute muscle inflammation induced by injection of carrageenan.
The NADPH-diaphorase activity and Fos-immunoreactivity within the ventral horn of the lumbar spinal cord were studied in cats with acute unilateral myositis following injection of carrageenan into the m.m. gastrocnemius-soleus. In carrageenan-injected cats maximum in the mean number of intensely stained NADPH-diaphorase reactive (NADPH-dr) neurons was found in lamina VII (+100%) and VIII (+33%) of the contralateral ventral horn of the L6/L7 segments as compared with control animals. The maximumal level of Fos-immunoreactivity was registered in the same laminae with ipsilateral predominance (39.3±4.6 and 7.6±0.9 cells), in comparison with the contralateral side (13.6±0.8 and 5.5±0.6 cells, respectively; P<0.05). We also visualized low-intensely stained and double labelled (Fos immunoreactive+low-intensely stained NADPH-dr) multipolar and fusiform Renshaw-like cells (RLCs) within the ventral horn on both sides of the L6/L7 segments in carrageenan-injected cats. We visualized the double labelled (Fos-ir+NADPH-dr) multipolar and fusiform Renshaw-like cells (RLCs) within the ventral horn on both sides of the L6/L7 segments in carrageenan-injected cats. A significant difference in the mean number of RLCs was recorded between the ipsi- and contralateral sides in the lamina VII (13.6±2.5 vs. 4.9±0.7 cells, respectively). We suppose that activation of inhibitory RLCs in ipsilateral lamina VII could be directed on attenuation of activation of motoneurons during muscle pain development. Our study showed that a significant contralateral increase in the number of NADPH-dr cells is accompanied by an ipsilateral increase in c-Fos expression in lamina VII. These data may suggest that NADPH-dr neurons of the contralateral ventral horn through commissural connections also involved in the maintenance of the neuronal activity associated with acute muscle inflammation. It is also hypothesized, that during acute myositis, plastic changes in the ventral horn activate the processes of disinhibition due to an increase in the number of NADPH-d-reactive neurons in the spinal gray matter.
Department of Brain Physiology, Bogomoletz Institute of Physiology, National Academy of Sciences, Bogomoletz Str. 4, Kiev 01024, Ukraine.
Vladimir A
VA
Maisky
Department of Brain Physiology, Bogomoletz Institute of Physiology, National Academy of Sciences, Bogomoletz Str. 4, Kiev 01024, Ukraine. Electronic address: elma4@ukr.net.
Olena P
OP
Mankivska
Department of Movement Physiology, Bogomoletz Institute of Physiology, National Academy of Sciences, Bogomoletz Str. 4, Kiev 01024, Ukraine.
Andriy V
AV
Maznychenko
Laboratory of Experimental Neurophysiology, Pirogov National Medical University, Ministry of Public Health of Ukraine, Pirogov Str. 56, Vinnitsa 21018, Ukraine.
Oleh V
OV
Vlasenko
Laboratory of Experimental Neurophysiology, Pirogov National Medical University, Ministry of Public Health of Ukraine, Pirogov Str. 56, Vinnitsa 21018, Ukraine.
Olexandr V
OV
Dovgan'
Institute of Physiology, Universität Göttingen, Humboldtallee 23, D-37073, Göttingen, Germany.
Eike D
ED
Schomburg
Institute of Physiology, Universität Göttingen, Humboldtallee 23, D-37073, Göttingen, Germany.
Heinz
H
Steffens
D000818:Animals; D002351:Carrageenan / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D002415:Cats; D004195:Disease Models, Animal; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D009249:NADP / Q000378:metabolism; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010146:Pain / Q000139:chemically induced; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism*
D016760:Proto-Oncogene Proteins c-fos; D009249:NADP; D002351:Carrageenan; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase
Cat; Fos-immunoreactivity; Muscle pain; NADPH-diaphorase reactivity; Renshaw-like cells; Spinal cord