Serotonin 5-HT7 receptor agonist, LP-211, exacerbates Na(+), K(+)-ATPase/Mg(2+)-ATPase imbalances in spinal cord-injured male rats

The influence of porcine epidemic diarrhea virus on pig small intestine mucosal epithelial cell function

Porcine epidemic diarrhea (PED) is a highly contagious, acute enteric tract infectious disease of pigs (Sus domesticus) caused by porcine epidemic diarrhea virus (PEDV). PED is characterized by watery diarrhea, dehydration, weight loss, vomiting and death. PEDV damages pig intestinal epithelial tissue, causing intestinal hyperemia and atrophy of intestinal villi, with formation of intestinal epithelial cell cytoplasmic vacuoles. Since pig small intestinal epithelial cells (IECs) are target cells of PEDV infection, IEC cells were utilized as a model for studying changes in cellular activities post-PEDV infection. Monitoring of Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase activities demonstrated that PEDV infection decreased these activities. In addition, IECs proliferation was shown to decrease after PEDV infection using an MTT assay. Moreover, IECs apoptosis detected by flow cytometry with propidium iodide (PI) staining was clearly shown to increase relative to the control group. Meanwhile, animal experiments indicated that PEDV virulence for IEC cells was greater than viral virulence for Vero cells, although this may be due to viral attenuation after numerous passages in the latter cell line. Collectively, these studies revealed viral pathogenic mechanisms in PEDV-infected IECs and offer a theoretical basis for PEDV prevention and control.

Pharmacophore Comparison and Development of Recently Discovered Long Chain Arylpiperazine and Sulfonamide Based 5-HT7 Ligands

The serotonin system exerts its effects on the CNS and many peripheral systems. Of the 14 serotonin receptors, the 5-HT7 receptor is the most recently discovered. The 5-HT7 receptor has been shown to be involved in stress reduction, depression, and nociceptive control. Despite the 20 years since the discovery of 5-HT7R, there are still few truly selective ligands. Two of the common scaffolds for 5-HT7R ligands are long chain arylpiperazines (LCAPs) and sulfonamide containing compounds. This review focuses on recently developed (2014-2016) 5-HT7R ligands, their selectivity for the receptor, and suggests the possible new pharmacophore models for these ligands.

Nanofiber Scaffolds as Drug Delivery Systems to Bridge Spinal Cord Injury

The complex pathophysiology of spinal cord injury (SCI) may explain the current lack of an effective therapeutic approach for the regeneration of damaged neuronal cells and the recovery of motor functions. A primary mechanical injury in the spinal cord triggers a cascade of secondary events, which are involved in SCI instauration and progression. The aim of the present review is to provide an overview of the therapeutic neuro-protective and neuro-regenerative approaches, which involve the use of nanofibers as local drug delivery systems. Drugs released by nanofibers aim at preventing the cascade of secondary damage (neuro-protection), whereas nanofibrous structures are intended to re-establish neuronal connectivity through axonal sprouting (neuro-regeneration) promotion, in order to achieve a rapid functional recovery of spinal cord.

Effect of 5-HT7 receptor agonist, LP-211, on micturition following spinal cord injury in male rats

BACKGROUND AND PURPOSE

Central and peripheral 5-hydroxytryptamine (5-HT) receptors play a critical role in regulation of micturition reflex. The aim of this study was to evaluate effect of a 5-HT7 receptor agonist, LP-211 (N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide) on micturition reflex in acute spinal cord-injured (SCI) rats during infusion of vehicle into the bladder.

METHODS

SCI was induced by compressing T10 segment using an aneurysm clip, extradurally in male rats. Following two weeks, LP-211 doses (0.003-0.3 mg/kg) were administered cumulatively (intraperitoneally, i.p.) with 20 min interval. The 5-HT7 antagonist, SB-269970 ((R)-3-[2-[2-(4-Methylpiperidin-1-yl) ethyl] pyrrolidine-1-sulfonyl] phenol hydrochloride), was administered after achievement of LP-211 dose-response. A cystometric study was performed 2 weeks after spinal crushing in all the animals. Cystometric variables consisting of micturition volume (voided volume), residual volume (volume remaining in the bladder after voiding), and bladder capacity (micturition volume plus residual volume). Voiding efficiency was calculated as the percent of micturition volume to bladder capacity.

FINDINGS

Intact and sham-operated rats showed few significant changes in micturition reflex. SCI rats responded to LP-211 (0.003-0.3, mg/kg, i.v.) with dose-dependent increases in bladder capacity, and residual volume. In this treatment group, LP-211 induced significant dose-dependent increases in micturition volume, resulting in significant increases in voiding efficiency (P<0.001) compared to intact and sham-operated rats, SB-269970 (0.1 mg/kg, i.v.) completely reversed the LP-211-induced changes on micturition volume and voiding efficiency was decreased significantly.

CONCLUSION

The 5-HT7 receptors activation by LP-211 facilitated the micturition reflex. Furthermore, 5-HT7 receptors do seem to play an important role in physiological regulation of micturition, and as a result, may represent a new strategy to improve voiding efficiency after SCI in patients in the future perspective.