It has been reported that in human neutrophils, external ATP activates plasma membrane purinergic P2X 7 receptors (P2X 7 R) to elicit Ca 2+ entry, production of reactive oxygen species (ROS), processing and release of pro-inflammatory cytokines, shedding of adhesion molecules and uptake of large molecules. However, the expression of P2X 7 R at the plasma membrane of neutrophils has also been questioned since these putative responses are not always reproduced. In this work, we used electrophysiological recordings to measure functional responses associated with the activation of membrane receptors, spectrofluorometric measurements of ROS production and ethidium bromide uptake to asses coupling of P2X 7 R activation to downstream effectors, immunelabelling of P2X 7 R using a fluorescein isothiocyanateconjugated antibody to detect the receptors at the plasma membrane, RT-PCR to determine mRNA expression of P2X 7 R and Western blot to determine protein expression in neutrophils and HL-60 cells. None of these assays reported the presence of P2X 7 R in the plasma membrane of neutrophils and non-differentiated or differentiated HL-60 cells-a model cell for human neutrophils. We concluded that P2X 7 R are not present at plasma membrane of human neutrophils and that the putative physiological responses triggered by external ATP should be reconsidered.

Aguilar Garcia et al. Restricted Cat Preparations Scratching Patterns Conclusion: Descending pathways and segmental afferent fibers, as well as 5-HT and WAY, can change the FS pattern. To our understanding, the half-center hypothesis is the most suitable for explaining the AP in MCC.

Taken together, these results show that perifosine modified the Kv2.1 inactivation gating resulting in a decrease of the current amplitude. These data will help to elucidate the mechanism of action of this promising anti-cancer drug on ion channels and their possible implications.

Ca(2+) influx through voltage-gated R-type (Ca(V)2.3) Ca(2+) channels is important for hormone and neurotransmitter secretion and other cellular events. Previous studies have shown that Ca(V)2.3 is both inhibited and stimulated through signaling mechanisms coupled to muscarinic ACh receptors. We previously demonstrated that muscarinic stimulation of Ca(V)2.3 is blocked by regulator of G protein signaling (RGS) 2. Here we investigated whether muscarinic inhibition of Ca(V)2.3 is antagonized by RGS3. RGS3 is particularly interesting because it contains a lengthy ( approximately 380 residue) amino-terminal domain of uncertain physiological function. Ca(V)2.3, M(2) muscarinic ACh receptors (M(2)R), and various deletion mutants of RGS3, including its native isoform RGS3T, were expressed in HEK293 cells, and agonist-dependent inhibition of Ca(V)2.3 was quantified using whole cell patch-clamp recordings. Full-length RGS3, RGS3T, and the core domain of RGS3 were equally effective in antagonizing inhibition of Ca(V)2.3 through M(2)R. These results identify RGS3 and RGS3T as potential physiological regulators of R-type Ca(2+) channels. Furthermore, they suggest that the signaling activity of RGS3 is unaffected by its extended amino-terminal domain. Confocal microscopy was used to examine the intracellular locations of four RGS3-enhanced green fluorescent protein fusion proteins. The RGS3 core domain was uniformly distributed throughout both cytoplasm and nucleus. By contrast, full-length RGS3, RGS3T, and the amino-terminal domain of RGS3 were restricted to the cytoplasm. These observations suggest that the amino terminus of RGS3 may serve to confine it to the cytoplasmic compartment where it can interact with cell surface receptors, heterotrimeric G proteins, and other signaling proteins.

Background: Spinal cord interneurons send their axons in the dorsal root. Their antidromic fire could modulate peripheral receptors. Thus, it could control pain, other sensorial modality, or muscle spindle activity. In this study, we assessed a staining technique to analyze whether interneurons send axons in the neonate mouse’s dorsal roots. We conducted experiments in 10 Swiss-Webster mice, which ranged in age from 2 to 13 postnatal days. We dissected the spinal cord and studied it in vitro. Results: We observed interneurons in the spinal cord dorsal horn sending axons through dorsal roots. A mix of fluorochromes applied in dorsal roots marked these interneurons. They have a different morphology than motoneurons. Primary afferent depolarization in afferent terminals produces antidromic action potentials (dorsal root reflex; DRR). These reflexes appeared by stimulation of adjacent dorsal roots. We found that in the presence of bicuculline, DRR recorded in the L4 dorsal root evoked by L5 dorsal root stimulation was reduced. Simultaneously, the monosynaptic reflex (MR) in the L5 ventral root was not affected; nevertheless, a long-lasting after discharge appeared. The addition of 2-amino-5 phosphonovalric acid (AP5), an antagonist of NMDA receptors, abolished the MR without changing the after discharge. Action potentials persisted in dorsal roots even in low Ca2+ concentration. Conclusions: Thus, firing interneurons could send their axons by dorsal roots. Antidromic potentials may be characteristics of the neonatal mouse, probably disappearing in adulthood.