Comparison of central versus peripheral delivery of pregabalin in neuropathic pain states

<p>Abstract</p> <p>Background</p> <p>Although pregabalin therapy is beneficial for neuropathic pain (NeP) by targeting the CaVα₂δ-1 subunit, its site of action is uncertain. Direct targeting of the central nervous system may be beneficial for the avoidance of systemic side effects.</p> <p>Results</p> <p>We used intranasal, intrathecal, and near-nerve chamber forms of delivery of varying concentrations of pregabalin or saline delivered over 14 days in rat models of experimental diabetic peripheral neuropathy and spinal nerve ligation. As well, radiolabelled pregabalin was administered to determine localization with different deliveries. We evaluated tactile allodynia and thermal hyperalgesia at multiple time points, and then analyzed harvested nervous system tissues for molecular and immunohistochemical changes in CaVα₂δ-1 protein expression. Both intrathecal and intranasal pregabalin administration at high concentrations relieved NeP behaviors, while near-nerve pregabalin delivery had no effect. NeP was associated with upregulation of CACNA2D1 mRNA and CaVα₂δ-1 protein within peripheral nerve, dorsal root ganglia (DRG), and dorsal spinal cord, but not brain. Pregabalin's effect was limited to suppression of CaVα₂δ-1 protein (but not CACNA2D1 mRNA) expression at the spinal dorsal horn in neuropathic pain states. Dorsal root ligation prevented CaVα₂δ-1 protein trafficking anterograde from the dorsal root ganglia to the dorsal horn after neuropathic pain initiation.</p> <p>Conclusions</p> <p>Either intranasal or intrathecal pregabalin relieves neuropathic pain behaviours, perhaps due to pregabalin's effect upon anterograde CaVα₂δ-1 protein trafficking from the DRG to the dorsal horn. Intranasal delivery of agents such as pregabalin may be an attractive alternative to systemic therapy for management of neuropathic pain states.</p

Clock mutation affects circadian regulation of circulating blood cells

BACKGROUND: Although the number of circulating immune cells is subject to high-amplitude circadian rhythms, the underlying mechanisms are not fully understood. METHODS: To determine whether intact CLOCK protein is required for the circadian changes in peripheral blood cells, we examined circulating white (WBC) and red (RBC) blood cells in homozygous Clock mutant mice. RESULTS: Daytime increases in total WBC and lymphocytes were suppressed and slightly phase-delayed along with plasma corticosterone levels in Clock mutant mice. The peak RBC rhythm was significantly reduced and phase-advanced in the Clock mutants. Anatomical examination revealed hemoglobin-rich, swollen red spleens in Clock mutant mice, suggesting RBC accumulation. CONCLUSION: Our results suggest that endogenous clock-regulated circadian corticosterone secretion from the adrenal gland is involved in the effect of a Clock mutation on daily profiles of circulating WBC. However, intact CLOCK seems unnecessary for generating the rhythm of corticosterone secretion in mice. Our results also suggest that CLOCK is involved in discharge of RBC from the spleen

G1 期後期への細胞周期の同期化および体細胞核移植胚の初期発生

体細胞核移植は、染色体の整合性の点から、細胞周期がG1 もしくはG0 期のドナー細胞が利用されているが、体細胞核移植胚の産子作出効率はいまだ低い。近年、分裂直後（G １期初期）の細胞を用いることでクローン産子の作出効率が向上したことが報告されている。しかしながら、この理由については明らかにされていない。そこで本研究では、G1 期の初期と後期の違いが初期発生に及ぼす影響を調べるため、まず、G1 期後期への同期化を試みた。ブロモデオキシウリジン（BrdU）標識法を用いて、M 期からS 期への移行時期を経時的に観察したところ、S 期の細胞は培養後10 時間まで増加し、その後一定となった。DNA 合成阻害剤である。Aphidicolin を含む培地でM 期の細胞を10 時間培養したところ、BrdU の取り込みが観察されなかったことから、G1 期後期としてドナー細胞として用いた。G1 期初期および後期に同期化したルシフェラーゼ遺伝子導入細胞を用いて核移植胚を作製し、経時的にルシフェラーゼ活性の測定を行ったところ、融合後60-96 時間においてG1 期初期の方が高い傾向であった。また、G1 期後期の細胞を用いた核移植胚の発生率および胚盤胞の細胞数は、G1 期初期と同等であった（発生率； 21％ vs 25％、細胞数； 69 ± 9 vs 105± 11 P>0.05）。以上のことから、G1 期初期および後期の違いは、胚盤胞の発生には影響を及ぼさないことが示された