<p>OBJECTIVETo construct a rat model of chronic nonbacterial prostatitis (CP) and investigate the difference in the quantitative expression of voltage-dependent calcium channels of prostate smooth muscle cells (PSMCs) between the models and controls.p><p>METHODSWe established a CP rat model by estrogen induction, cultured and purified the PSMCs in vitro, and extracted total RNA by Trizol. Then we measured the mRNA expression of the cal subunit in the calcium channel subtypes by reverse transcription and SYBR Green I real time RT-PCR, and compared it with that of the controls.p><p>RESULTSThe expressions of the L-, T- and P/Q-type calcium channels were found in both the CP and control groups, and that of the CaV1.2 L-type calcium channel was significantly increased in the former as compared with the latter (0.048 +/- 0.024 versus 0.031 +/- 0.015, t = 2.846, P = 0.007), but there were no statistically significant differences in the T- and P/Q-type calcium channels between the two groups.p><p>CONCLUSIONThe number of CaV1.2 L-type calcium channels of PSMCs and calcium influx were increased in CP patients, which may be involved in the mechanism of CP.p>
Animals ; Calcium Channels, L-Type ; metabolism ; Calcium Channels, Q-Type ; metabolism ; Calcium Channels, T-Type ; metabolism ; Estradiol ; pharmacology ; Male ; Myocytes, Smooth Muscle ; metabolism ; Prostate ; metabolism ; Prostatitis ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar

Voltage dependent calcium channel (VDCC), one of the most important regulator of Ca2+ concentration in neuron, play an essential role in the central processing of nociceptive information. The present study investigated the antinociceptive effects of L, T or N type VDCC blockers on the formalin-induced orofacial inflammatory pain. Experiments were carried out on adult male Sprague-Dawley rats weighing 220-280 g. Anesthetized rats were individually fixed on a stereotaxic frame and a polyethylene (PE) tube was implanted for intracisternal injection. After 72 hours, 5% formalin (50 microL) was applied subcutaneously to the vibrissa pad and nociceptive scratching behavior was recorded for nine successive 5 min intervals. VDCC blockers were administered intracisternally 20 minutes prior to subcutaneous injection of formalin into the orofacial area. The intracisternal administration of 350 or 700 microg of verapamil, a blocker of L type VDCC, significantly decreased the number of scratches and duration in the behavioral responses produced by formalin injection. Intracisternal administration of 75 or 150 microg of mibefradil, a T type VDCC blocker, or 11 or 22 microg of cilnidipine, a N type VDCC blocker, also produced significant suppression of the number of scratches and duration of scratching in the first and second phase. Neither intracisternal administration of all VDCC blockers nor vehicle did not affect in motor dysfunction. The present results suggest that central VDCCs play an important role in orofacial nociceptive transmission and a targeted inhibition of the VDCCs is a potentially important treatment approach for inflammatory pain originating in the orofacial area.
Adult ; Animals ; Calcium ; Calcium Channel Blockers ; Calcium Channels ; Calcium Channels, L-Type ; Calcium Channels, N-Type ; Calcium Channels, T-Type ; Dihydropyridines ; Facial Pain ; Formaldehyde ; Humans ; Injections, Subcutaneous ; Male ; Mibefradil ; Neurons ; Pain Measurement ; Polyethylene ; Rats ; Rats, Sprague-Dawley ; Verapamil

Nitric oxide (NO) elevates intracellular calcium. But the actions of calcium in NO-induced cell death are not well understood. This study was carried out to investigate the signal transduction pathways of calcium and NO-induced cytotoxicity in H9c2 cardiac myoblasts by using NO donor compounds such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP). Pretreatment of intracellular calcium chelating agent (BAPTA/AM) or L-type calcium channel blockers (nicardipine, nifedipine, diltiazem and veraparmil) or T-type calcium channel blocker (flunarizine) blocked SNP-induced cytotoxicity respectively only in a three hours. However, thapsigargin (TG), which inhibits endoplasmic reticulum dependent Ca(2+)-ATPase and thereby increases cytosolic Ca(2+), augmented SNP-induced cytotoxicity. The protective effect of BAPTA/AM was inhibited by treatment of protein synthesis inhibitor, cyclohexamide. In addition, pyrrolidine dithiocarbamate (PDTC), NF-kB inhibitor, attenuates the protective effect of BAPTA/AM against SNP-induced cytotoxicity. It is indicated that the protective effect of BAPTA/AM against NO-induced cytotoxicity might be due to the expression of protein related to activation of NFkB. From these results, it is concluded that SNP-induced cytotoxicity is mediated by calcium in a 3 hours via down regulation of protein expression rleated to activation of NFkB.
Calcium Channels, L-Type ; Calcium Channels, T-Type ; Calcium* ; Cell Death ; Cytosol ; Diltiazem ; Down-Regulation ; Endoplasmic Reticulum ; Humans ; Myoblasts, Cardiac* ; NF-kappa B ; Nifedipine ; Nitric Oxide ; Nitroprusside ; S-Nitroso-N-Acetylpenicillamine ; Signal Transduction* ; Thapsigargin ; Tissue Donors

Melittin-induced nociceptive responses are mediated by selective activation of capsaicin-sensitive primary afferent fibers and are modulated by excitatory amino acid receptor, cyclooxygenase, protein kinase C and serotonin receptor. The present study was undertaken to investigate the peripheral and spinal actions of voltage-gated calcium channel antagonists on melittin-induced nociceptive responses. Changes in mechanical threshold and number of flinchings were measured after intraplantar (i.pl.) injection of melittin (30microg/paw) into mid-plantar area of hindpaw. L-type calcium channel antagonists, verapamil [intrathecal (i.t.), 6 or 12microg; i.pl.,100 & 200microg; i.p., 10 or 30 mg], N-type calcium channel blocker, omega-conotoxin GVIA (i.t., 0.1 or 0.5microg; i.pl., 5microg) and P-type calcium channel antagonist, omega-agatoxin IVA (i.t., 0.5microg; i.pl., 5microg) were administered 20 min before or 60 min after i.pl. injection of melittin. Intraplantar pre-treatment and i.t. pre- or post-treatment of verapamil and omega-conotoxin GVIA dose-dependently attenuated the reduction of mechanical threshold, and melittin-induced flinchings were inhibited by i.pl. or i.t. pre-treatment of both antagonists. P-type calcium channel blocker, omega-agatoxin IVA, had significant inhibitory action on flinching behaviors, but had a limited effect on melittin-induced decrease in mechanical threshold. These experimental findings suggest that verapamil and omega-conotoxin GVIA can inhibit the development and maintenance of melittin-induced nociceptive responses.
Animals ; Calcium Channels* ; Calcium Channels, L-Type ; Calcium Channels, N-Type ; Calcium Channels, P-Type ; Calcium* ; Hyperalgesia ; Ions* ; Melitten ; Nociception* ; omega-Agatoxin IVA ; omega-Conotoxin GVIA ; Prostaglandin-Endoperoxide Synthases ; Protein Kinase C ; Rats* ; Receptors, Glutamate ; Serotonin ; Verapamil

Depending on the intracellular buffering of calcium by chelation, zinc has the following two apparent effects on neuronal excitability: enhancement or reduction. Zinc increased tonic activity in the depolarized state when neurons were intracellularly dialyzed with EGTA but attenuated the neuronal activity when BAPTA was used as an intracellular calcium buffer. This suggests that neuronal excitability can be modulated by zinc, depending on the internal calcium buffering capacity. In this study, we elucidated the mechanisms of zinc-mediated alterations in neuronal excitability and determined the effect of calcium-related channels on zinc-mediated alterations in excitability. The zinc-induced augmentation of firing activity was mediated via the inhibition of small-conductance calcium-activated potassium (SK) channels with not only the contribution of voltage-gated L-type calcium channels (VGCCs) and ryanodine receptors (RyRs), but also through the activation of VGCCs via melastatin-like transient receptor potential channels. We suggest that zinc modulates the dopaminergic neuronal activity by regulating not only SK channels as calcium sensors, but also VGCCs or RyRs as calcium sources. Our results suggest that the cytosolic calcium-buffering capacity can tightly regulate zinc-induced neuronal firing patterns and that local calcium-signaling domains can determine the physiological and pathological state of synaptic activity in the dopaminergic system.
Animals ; Calcium ; Calcium Channels, L-Type ; Cytosol ; Dopaminergic Neurons ; Egtazic Acid ; Electrophysiology ; Fires ; Neurons ; Potassium ; Rats ; Ryanodine Receptor Calcium Release Channel ; Transient Receptor Potential Channels ; Zinc

Thyroid hormone-induced cellular dysfunctions may be associated with changes in the intracellular Ca2+ concentration. The ryanodine receptor, a Ca2+ release channel of the SR, is responsible for the rapid release of Ca2+ that activates cardiac muscle contraction. In the excitation-contaction coupling cascade, activation of ryanodine receptors is initiated by the activity of sarcolemmal Ca2+ channels, the dihydropyridine receptors. In hyperthyroidism left ventricular contractility and relaxation velocity were increased, whereas these parameters were decreased in hypothyroidism. The mechanisms for these changes have been suggested to include alterations in the expression and/or activity levels of various proteins. In the present study, quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of these changes in various thyroid states were investigated. In hyperthyroid hearts, (3H)ryanodine binding and ryanodine receptor mRNA levels were increased, but protein levels of ryanodine were not changed significantly. However, the above parameters were markedly decreased in hypothyroid hearts. In case of dihydropyridine receptor, there were a significant increase in the mRNA and protein levels, and (3H)nitrendipine binding, whereas no changes were observed in these parameters of hypothyroid hearts. Our findings indicate that hyperthyroidism is associated with increases in ryanodine receptor and dihydropyridine receptor expression levels, which is well correlated with the ryanodine and dihydropyridine binding. Whereas opposite changes occur in ryanodine receptor of the hypothyroid hearts.
Animals ; Calcium Channels, L-Type* ; Heart ; Hyperthyroidism ; Hypothyroidism ; Myocardium ; Rats* ; Relaxation ; RNA, Messenger ; Ryanodine Receptor Calcium Release Channel ; Ryanodine* ; Thyroid Gland*

We studied the excitatory action of morphine on the responses of dorsal horn neuron to iontophoretic application of excitatory amino acid and C-fiber stimulation by using the in vivo electrophysiological technique in the rat. In 137 of the 232 wide dynamic range (WDR) neurons tested, iontophoretic application of morphine enhanced the WDR neuron responses to N-methyl-D-aspartate (NMDA), kainate, and graded electrical stimulation of C-fibers. Morphine did not have any excitatory effects on the responses of low threshold cells. Morphine-induced excitatory effect at low ejection current was naloxone-reversible and reversed to an inhibitory action at high ejection current. NMDA receptor, calcium channel and intracellular Ca2+ antagonists strongly antagonized the morphine-induced excitatory effect. These results suggest that changes in intracellular ionic concentration, especially Ca2+, play an important role in the induction of excitatory effect of morphine in the rat dorsal horn neurons.
Animals ; Calcium Channels ; Calcium Channels, L-Type* ; Electric Stimulation ; Excitatory Amino Acids ; Kainic Acid ; Morphine* ; N-Methylaspartate* ; Neurons ; Posterior Horn Cells ; Rats

<p>OBJECTIVETo study the expression of the L-type calcium channel (Cav1.3) and its receptor Ryrs1 in the corpus cavernosum of the penis in aged rats, and to explore the mechanism of age-related erectile dysfunction (ED).p><p>METHODSWe included 10 two month-old male SD rats (Group A) and another ten 18-month-old ones (Group B) in this study, measured their serum testosterone levels and analyzed the expressions of Cav1.3 and RyR1 in the corpus cavernosum of the penis by RT-PCR and immunohistochemistry.p><p>RESULTSThe level of serum testosterone was significantly lower in Group B than in A ([1 356 +/- 424] ng/L vs [2 744 +/- 964] ng/L, P < 0.05). Compared with the young rats, the aged ones showed significant decreases in the expressions of Cav1.3 (IA = 18.65 +/- 8.47 vs 75.48 +/- 14.28, P < 0.05), RyR1 (IA = 21.37 +/- 9.64 vs 78.23 +/- 13.57, P < 0.05), Cav1.3 mRNA (mean gray value = 0.382 +/- 0.046 vs 1.137 +/- 0.415, P < 0.05), and RyR1 mRNA (mean gray value = 0.146 +/- 0.053 vs 1.215 +/- 0.261, P < 0.05).p><p>CONCLUSIONReduced expressions of Cav1.3 and RyR1 in the corpus cavernosum of the penis may be one of the mechanisms underlying age-related ED in aged rats.p>
Aging ; Animals ; Calcium Channels, L-Type ; metabolism ; Erectile Dysfunction ; metabolism ; Male ; Penis ; metabolism ; Rats ; Rats, Sprague-Dawley ; Ryanodine Receptor Calcium Release Channel ; metabolism

<p>AIMTo elucidate the possible mechanisms underlying antiarrhythmia of the non-selective Na+/H+ exchanger inhibitor--amiloride.p><p>METHODSSingle ventricular cells were isolated using a double-enzyme method. Effects of amiloride on voltage-dependent potassium and calcium currents in isolated guinea pig ventricular myocyte were recorded by using whole-cell patch clamp techniques.p><p>RESULTSExposure to amiloride (10 -100 micromol x L(-1)), the L-type and T-type calcium currents were depressed. Amiloride resulted in a concentration-dependent inhibition of peak (Ca,L), But amiloride did not change the shape of their I - V curves. It only decreased the amplitudes of the currents of the two types. When myocytes were incubated with 100 micromol x L(-1) amiloride, I(Kr) was slightly depressed and I(Ks) did not change. Amiloride (1 - 100 micromol x L(-10) depressed I(K1) in a concentration-dependent manner.p><p>CONCLUSIONAmiloride depressed potassium and calcium currents, which may give support to its uses in some diseases of the cardiovascular system.p>
Amiloride ; pharmacology ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Calcium Channels, L-Type ; drug effects ; Calcium Channels, T-Type ; drug effects ; Cell Separation ; Female ; Guinea Pigs ; Heart Ventricles ; cytology ; Male ; Myocytes, Cardiac ; drug effects ; Patch-Clamp Techniques ; Potassium Channels, Inwardly Rectifying ; drug effects ; Potassium Channels, Voltage-Gated ; drug effects ; Sodium-Hydrogen Exchangers ; antagonists & inhibitors

The ryanodine receptor, a Ca2+ release channel of the sarcoplasmic reticulum (SR), is responsible for the rapid release of Ca2+ that activates cardiac muscle contraction. In the excitation-contraction coupling cascade, activation of SR Ca2+ release channel is initiated by the activity of sarcolemmal Ca2+ channels, the dihydropyridine receptors. Previous study showed that the relaxation defect of diabetic heart was due to the changes of the expressional levels of SR Ca2+ ATPase and phospholamban. In the diabetic heart contractile abnormalities were also observed, and one of the mechanisms for these changes could include alterations in the expression and/or activity levels of various Ca2+ regulatory proteins involving cardiac contraction. In the present study, underlying mechanisms for the functional derangement of the diabetic cardiomyopathy were investigated with respect to ryanodine receptor, and dihydropyridine receptor at the transcriptional and translational levels. Quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of those changes in diabetic heart were investigated. The levels of protein and mRNA of the ryanodine receptor in diabetic rats were comparable to these of the control. However, the binding capacity of ryanodine was significantly decreased in diabetic rat hearts. Furthermore, the reduction in the binding capacity of ryanodine receptor was completely restored by insulin. This result suggests that there were no transcriptional and translational changes but functional changes, such as conformational changes of the Ca2+ release channel, which might be regulated by insulin. The protein level of the dihydropyridine receptor and the binding capacity of nitrendipine in the sarcolemmal membranes of diabetic rats were not different as compared to these of the control. In conclusion, in diabetic hearts, Ca2+ release processes are impaired, which are likely to lead to functional derangement of contraction of heart. This dysregulation of intracellular Ca2+ concentration could explain for clinical findings of diabetic cardiomyopathy and provide the scientific basis for more effective treatments of diabetic patients. In view of these results, insulin may be involved in the control of intracellular Ca2+ in the cardiomyocyte via unknown mechanism, which needs further study.
Animals ; Calcium Channels, L-Type ; Calcium-Transporting ATPases ; Diabetic Cardiomyopathies* ; Heart ; Humans ; Insulin ; Membranes ; Myocardium ; Myocytes, Cardiac ; Nitrendipine ; Rats* ; Relaxation ; RNA, Messenger ; Ryanodine Receptor Calcium Release Channel* ; Ryanodine* ; Sarcoplasmic Reticulum*