Cav2.3 (α1E) Ca2+ channel participates in the control of sperm function

AbstractTo know the function of the Ca2+ channel containing α12.3 (α1E) subunit (Cav2.3 channel) in spermatozoa, we analyzed Ca2+ transients and sperm motility using a mouse strain lacking Cav2.3 channel. The averaged rising rates of Ca2+ transients induced by α-D-mannose–bovine serum albumin in the head region of Cav2.3−/− sperm were significantly lower than those of Cav2.3+/+ sperm. A computer-assisted sperm motility assay revealed that straight-line velocity and linearity were greater in Cav2.3−/− sperm than those in Cav2.3+/+ sperm. These results suggest that the Cav2.3 channel plays some roles in Ca2+ transients and the control of flagellar movement

Upregulation of casein kinase 1ε in dorsal root ganglia and spinal cord after mouse spinal nerve injury contributes to neuropathic pain

<p>Abstract</p> <p>Background</p> <p>Neuropathic pain is a complex chronic pain generated by damage to, or pathological changes in the somatosensory nervous system. Characteristic features of neuropathic pain are allodynia, hyperalgesia and spontaneous pain. Such abnormalities associated with neuropathic pain state remain to be a significant clinical problem. However, the neuronal mechanisms underlying the pathogenesis of neuropathic pain are complex and still poorly understood. Casein kinase 1 is a serine/threonine protein kinase and has been implicated in a wide range of signaling activities such as cell differentiation, proliferation, apoptosis, circadian rhythms and membrane transport. In mammals, the CK1 family consists of seven members (α, β, γ1, γ2, γ3, δ, and ε) with a highly conserved kinase domain and divergent amino- and carboxy-termini.</p> <p>Results</p> <p>Preliminary cDNA microarray analysis revealed that the expression of the <it>casein kinase 1 epsilon </it>(<it>CK1ε</it>) mRNA in the spinal cord of the neuropathic pain-resistant N- type Ca²⁺channel deficient (<it>Ca</it>_<it>v</it><it>2.2</it>^-/-) mice was decreased by the spinal nerve injury. The same injury exerted no effects on the expression of <it>CK1ε </it>mRNA in the wild-type mice. Western blot analysis of the spinal cord identified the downregulation of CK1ε protein in the injured <it>Ca</it>_<it>v</it><it>2.2</it>^-/-mice, which is consistent with the data of microarray analysis. However, the expression of CK1ε protein was found to be up-regulated in the spinal cord of injured wild-type mice. Immunocytochemical analysis revealed that the spinal nerve injury changed the expression profiles of CK1ε protein in the dorsal root ganglion (DRG) and the spinal cord neurons. Both the percentage of CK1ε-positive neurons and the expression level of CK1ε protein were increased in DRG and the spinal cord of the neuropathic mice. These changes were reversed in the spinal cord of the injured <it>Ca</it>_<it>v</it><it>2.2</it>^-/-mice. Furthermore, intrathecal administration of a CK1 inhibitor IC261 produced marked anti-allodynic and anti-hyperalgesic effects on the neuropathic mice. In addition, primary afferent fiber-evoked spinal excitatory responses in the neuropathic mice were reduced by IC261.</p> <p>Conclusions</p> <p>These results suggest that CK1ε plays important physiological roles in neuropathic pain signaling. Therefore CK1ε is a useful target for analgesic drug development.</p

G-Protein Modulation of Neuronal Class E (α1E) Calcium Channel Expressed in GH3Cells

GH3cell lines stably expressing α1Echannel were established and the modulation of this channel by G-protein through membrane-delimited pathways was studied. α1Echannel expressed in GH3cells showed slowing of activation and reduction of current amplitude by the application of carbachol or somatostatin. Both of these effects caused by these agents were pertussis toxin (PTX) sensitive and voltage dependent. Dialysis of the cell interior with GTPγS mimicked the action of these externally applied neurotransmitters, indicating that the α1Echannel is modulated by the PTX sensitive G-protein(s) through the membrane-delimited pathway but not by the PTX insensitive pathway that has been observed in α1Achannel expressed in GH3cells. Thus different types of neuronal Ca2+channels can be modulated not only by a similar mechanism but also by a different mechanism conferring a multilateral regulation of Ca2

G-Protein Modulation of α1A (P/Q)-Type Calcium Channel Expressed in GH3 Cells

GH(3) cell lines stably expressing α1A channel were established and the modulation of this channel by G-protein through membrane-delimited pathways were studied. Wild type GH(3) cells were found to express ω-conotoxin MVIIC (MVIIC) sensitive Ca2+ current but this component was different from the α1A channel because of its susceptibility to G-protein modulation, suggesting MVIIC also blocks channels other than P/Q type. α1A channel expressed in GH3 cells showed slowing of activation and reduction of current amplitude by the application of carbachol. Both of these effects were pertussis toxin (PTX) sensitive and voltage dependent. α1A channels were also found to be modulated through a PTX insensitive pathway, the modulations observed were similar to those in the PTX sensitive pathway. The results further suggest that these two effects are governed by a different mechanism in both PTX sensitive and

Suppression of inflammatory and neuropathic pain symptoms in mice lacking the N-type Ca(2+) channel

The importance of voltage-dependent Ca(2+) channels (VDCCs) in pain transmission has been noticed gradually, as several VDCC blockers have been shown to be effective in inhibiting this process. In particular, the N-type VDCC has attracted attention, because inhibitors of this channel are effective in various aspects of pain-related phenomena. To understand the genuine contribution of the N-type VDCC to the pain transmission system, we generated mice deficient in this channel by gene targeting. We report here that mice lacking N-type VDCCs show suppressed responses to a painful stimulus that induces inflammation and show markedly reduced symptoms of neuropathic pain, which is caused by nerve injury and is known to be difficult to treat by currently available therapeutic methods. This finding clearly demonstrates that the N-type VDCC is essential for development of neuropathic pain and, therefore, controlling the activity of this channel can be of great importance for the management of neuropathic pain