Specific neuronal populations are known to express calcium binding proteins (CBP) such as calbindin (CB), parvalbumin (PV) and calretinin (CR). These CBP can act as calcium buffers that modify spatiotemporal characteristics of intracellular calcium transients and affect calcium homeostasis in neurons. It was recently shown that changes in neuronal CBP expression can have significant modulatory effect on synaptic transmission. Spinothalamic tract (STT) neurons form a major nociceptive pathway and they become sensitized after peripheral inflammation. In our experiments, expression of CBP in STT neurons was studied in a model of unilateral acute knee joint arthritis in rats. Altogether 377, 374 and 358 STT neurons in the segments L3-4 were evaluated for the presence of CB, PV and CR. On the contralateral (control) side 11 %, 9 % and 47 % of the retrogradely labeled STT ne urons expressed CB, PV and CR, respectively. On the ipsilateral (arthritic) side there was significantly more CB (23 %) and PV (25 %) expressing STT neurons, while the number of CR positive neurons (50 %) did not differ. Our results show increased expression of fast (CB) and slow (PV) calcium binding proteins in STT neurons after induction of experimental arthritis. This suggests that change in CBP expression could have a significant effect on calcium homeostasis and possibly modulation of synaptic activity in STT neurons., D. Sojka, G. Zacharova, D. Spicarova, J. Palecek., and Obsahuje bibliografii
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 ca lcium 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 wa s 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., G. Zachařová, D. Sojka, J. Paleček., and Obsahuje bibliografii
a1_We have investigated expression of skeletal calsequestrin (CSQ1) and fiber type composition in normal and regenerated fast and slow skeletal muscles and in the left heart ventricles of euthyroid (EU), hypothyroid (HY) and hyperthyroid (TH) adult inbred Lewis strain rats. The CSQ1 level was determined by SDS-PAGE followed by Western blot analysis. CSQ1 gene expression was assessed using reverse transcription and subsequent real time polymerase chain reaction. Muscle regeneration was achieved by intramuscular grafting of either soleus or extensor digitorum longus (EDL) from 3- to 4-week-old rats to either EDL or soleus muscle of 2-month-old rats. The fiber type composition was assessed by a stereological method applied to stained muscle cross sections. We found that the protein and mRNA levels for CSQ1 were highest in the EDL muscle, the relative CSQ1 protein levels in the soleus muscle were two times lower and the transcript levels more than 5 times lower compared to the EDL. In the left heart ventricle, protein isoform and CSQ1 transcript were also present, although at protein level, CSQ1 was hardly detectable. TH status increased and HY status decreased the expression of CSQ1 in the EDL, but its relative levels in the soleus and in the heart did not change. The regenerated soleus transplanted into EDL, as well as EDL transplanted into soleus exhibited protein and mRNA levels of CSQ1 corresponding to the host muscle and not to the graft source. TH status increased the percentages of the fastest 2X/D and 2B fibers at the expense of slow type 1 and fast 2A fibers in the EDL and that of fast 2A fibers in the soleus at the expense of slow type 1 fibers. HY status led to converse fiber type changes., a2_We suggest that the observed changes in CSQ1 levels in TH and HY compared to EU rats can be related to fiber type changes caused by alteration of the thyroid status rather than to the direct effect of thyroid hormones on CSQ1 gene expression., T. Soukup ... [et al.]., and Obsahuje seznam literatury
Expression of parvalbumin (PV) and transient receptor potential vanilloid (TRPV1) receptors in the lumbar dorsal root ganglion neurons (DRG) was evaluated in control animals and in rats after acute carageenan-induced knee joint inflammation. PV is a calcium binding protein that acts as a calcium buffer, affects intracellular calcium homeostasis and may thus influence signal transduction and synaptic transmission. TRPV1 receptors are viewed as molecular integrators of nociceptive stimuli and modulate spinal cord synaptic transmission beside their function in the peripheral nerve endings. In naive rats, 13 % of the L4 DRG neurons had PV immunopositivity (PV+) and 36 % expressed TRPV1 receptors (TRPV1+). The soma of the PV+ neurons was of medium to large size, while the TRPV1 receptors were expressed in small diameter neurons. The co-localization of the PV and TRPV1 immunoreactivity was minimal (0.2 %). There was no significant change in the PV+ (11 %), TRPV1+ (42 %) and PV+TRPV1+ (0.25 %) expression, or shift in the neuronal size distribution 28 h after the unilateral peripheral inflammation, both when compared to controls and when ipsilateral to contralateral sides were evaluated. Thus under the given experimental conditions, no change in somatic TRPV1 receptors and PV expression in L4 DRG neurons was found., G. Zachařová, J. Paleček., and Obsahuje seznam literatury
Transient receptor potential vanilloid 1 (TRPV1) receptor is a nonselective cation channel activated by capsaicin, a pungent substance from chili peppers. It is considered to act as an integrator of various physical and chemical nociceptive stimuli, as it can be gated by noxious heat (>43ºC), low pH (protons) and also by recently described endogenous lipids. The structure and function of TRPV1 receptors was vigorously studied, especially since its cloning in 1997. However, most of the research was pointed towards the role of TRPV1 receptors in the peripheral tissues. Mounting evidence now suggests that TRPV1 receptors on the central branches of dorsal root ganglion neurons in the spinal cord may play an important role in modulation of pain and nociceptive transmission. The aim of this short review was to summarize the knowledge about TRPV1 receptors in the spinal cord dorsal horn, preferentially from morphological and electrophysiological studies on spinal cord slices and from in vivo experiments., D. Špicarová, J. Paleček., and Obsahuje bibliografii a bibliografické odkazy
The structure, expression and function of the transient receptor potential vanilloid 1 (TRPV1) receptor were intensively studied since the cloning in 1997 and TRPV1 receptors are now considered to act as transducers and molecular integrators of nociceptive stimuli in the periphery. In contrast, spinal TRPV1 receptors were studied less extensively and their role in pain modulation is still not fully understood. This short review is a follow up on our previous summary in this area ( Spicarova and Palecek 2008). The aim was to review preferentially the most recent findings concerning the role of the spinal TRPV1 receptors, published within the last five years. The update is given on the expression and function of the spinal TRPV1 receptors, their activation by endogenous agonists, interaction between the endocannabinoid and endovanillod system and possible role of the spinal TRPV1 receptors in pathological pain states. There is now mounting evidence that TRPV1 receptors may be an important element in modulation of nociceptive information at the spinal cord level and represent an interesting target for analgesic therapy., D. Spicarova, V. Nerandzic, J. Palecek., and Obsahuje bibliografii a bibliografické odkazy