Parvalbumin (PV) is a calcium-binding protein that is expressed
by numerous neuronal subpopulations in the central nervous
system. Staining for PV was often used in neuroanatomical
studies in the past. Recently, several studies have suggested that
PV acts in neurons as a mobile endogenous calcium buffer that
affects temporo-spatial characteristics of calcium transients and
is involved in modulation of synaptic transmission. In our
experiments, expression of PV in the lumbar dorsal horn spinal
cord was evaluated using densitometric analysis of
immunohistological sections and Western-blot techniques in
control and arthritic rats. There was a significant reduction of PV
immunoreactivity in the superficial dorsal horn region ipsilateral
to the arthritis after induction of the peripheral inflammation. The
ipsilateral area and intensity of PV staining in this area were
reduced to 38 % and 37 %, respectively, out of the total PV
staining on both sides. It is suggested that this reduction may
reflect decreased expression of PV in GABAergic inhibitory
neurons. Reduction of PV concentration in the presynaptic
GABAergic terminals could lead to potentiation of inhibitory
transmission in the spinal cord. Our results suggest that changes
in expression of calcium-binding proteins in spinal cord dorsal
horn neurons may modulate nociceptive transmission.
Genetically Defined Inhibitory Neurons in the Mouse Spinal Cord Dorsal Horn: A Possible Source of Rhythmic Inhibition of Motoneurons during Fictive Locomotion
