Inositol 1,4,5-trisphosphate receptor 1 (ITPR1) is an important intracellular channel for releasing Ca²⁺. In order to investigate the effects of the ITPR1 overexpression on Ca²⁺ concentration and lipid content in duck uterine epithelial cells and its effects on calcium transport-related genes, the structural domain of ITPR1 gene of duck was cloned into an eukaryotic expression vector and transfected into duck uterine epithelial cells. The overexpression of the ITPR1 gene, the concentration of Ca²⁺, the lipid content, and the expression of other 6 calcium transport-related genes was determined. The results showed that the concentration of Ca²⁺ in uterine epithelial cells was significantly reduced after transfection (P<0.05), the triglyceride content was significantly increased (P<0.01), and the high-density lipoprotein content was significantly decreased (P<0.01). The correlation analysis results showed that the overexpression of the C-terminal half of the ITPR1 gene was significantly positively correlated with the total cholesterol content (P<0.01), which was significantly positively correlated with the low-density lipoprotein content (P<0.05). The overexpression of the N-terminal half of the ITPR1 gene was significantly positively correlated with the triglyceride content (P<0.01), which was significantly negatively correlated with the concentration of Ca²⁺ (P<0.05). RT-qPCR results of 6 calcium transport-related genes showed that the overexpression of the C-terminal half of the ITPR1 gene significantly inhibited the expression of the IP3R2, VDAC2 and CAV1 genes, and the overexpression of the N-terminal half of the ITPR1 gene significantly promoted the expression of the IP3R3 and CACNA2D1 genes. In conclusion, the ITPR1 gene overexpression can promote Ca²⁺ release in duck uterus epithelial cells, promote the synthesis of triglyceride, low-density lipoprotein and cholesterol, and inhibit the production of high-density lipoprotein, and the ITPR1 gene overexpression affected the expression of all 6 calcium transport-related genes.
Animals ; Calcium/metabolism* ; Ducks/genetics* ; Epithelial Cells ; Female ; Inositol ; Inositol 1,4,5-Trisphosphate Receptors ; Lipids ; Uterus

Radiation therapy for variety of human solid tumors utilizes mechanism of cell death after DNA damage caused by radiation. In response to DNA damage, cytochrome c was released from mitochondria by activation of pro-apoptotic Bcl-2 family proteins, and then elicits massive Ca2+ release from the ER that lead to cell death. It was also suggested that irradiation may cause the deregulation of Ca2+ homeostasis and trigger programmed cell death and regulate death specific enzymes. Thus, in this study, we investigated how cellular Ca2+ metabolism in RKO cells, in comparison to radiation-resistant A549 cells, was altered by gamma (gamma)-irradiation. In irradiated RKO cells, Ca2+ influx via activation of NCX reverse mode was enhanced and a decline of [Ca2+]i via forward mode was accelerated. The amount of Ca2+ released from the ER in RKO cells by the activation of IP3 receptor was also enhanced by irradiation. An increase in [Ca2+]i via SOCI was enhanced in irradiated RKO cells, while that in A549 cells was depressed. These results suggest that gamma-irradiation elicits enhancement of cellular Ca2+ metabolism in radiation-sensitive RKO cells yielding programmed cell death.
Calcium* ; Cell Death ; Colorectal Neoplasms* ; Cytochromes c ; DNA Damage ; Homeostasis ; Humans ; Inositol 1,4,5-Trisphosphate Receptors ; Metabolism* ; Mitochondria

Cytosolic Ca(2+) ions play an important role in the regulation of numerous aspects of cellular activity in virtually all cell types. There is a complex interaction between the neuronal electrical signals on plasma membrane and the chemical signals of intracellular calcium. Each neuron can be considered as a binary membrane system with plasma membrane and endoplasmic reticulum membrane, and the neuronal endoplasmic reticulum can be regarded as a neuron-within-a-neuron. This review explores the simulation modeling of neuronal dynamics mutually coupled with the intracellular calcium signaling released from endoplasmic reticulum through the inositol 1,4,5-trisphosphate receptor calcium channels. We show that a current trend is to include the intracellular calcium dynamics into the neuronal models, and the frontier of this research is now shifting to spatial neuronal models with diffusing intracellular calcium. It is expected that more important results will be obtained with the neuronal models incorporating the intracellular calcium dynamics, especially the spatial models considering the calcium diffusion both in soma and dendritic branches.
Animals ; Calcium ; metabolism ; Calcium Signaling ; physiology ; Cytosol ; metabolism ; Endoplasmic Reticulum ; metabolism ; physiology ; Humans ; Inositol 1,4,5-Trisphosphate Receptors ; metabolism ; Models, Neurological ; Neurons ; metabolism ; physiology

D-myo-inositol 1,4,5-trisphosphate (IP(3)) plays an important role in signal transduction. It releases Ca(2+) from intracellular sites, which activates the Ca(2+)-dependent channels such as large-conductance Ca(2+)-activated potassium channels (BK channels). The present study was therefore designed to determine if the activity of BK channels in porcine coronary artery smooth muscle cells was increased by IP(3). Using the inside-out patch-clamp technique, the activity of single BK channels was recorded in porcine coronary artery smooth muscle cells. In excised inside-out membrane patches, IP(3) (10-50 micromol/L) enhanced the open probability (Po) of BK channels in a dose-dependent manner in the intracellular side of inside-out patches and its effect was almost completely abolished by washout. The open-state probability of the BK channels increased from a control level of 0.0402+/-0.0152 to 0.1365+/-0.0212 (20 micromol/L IP(3)) and 0.1865+/-0.0175 (30 micromol/L IP(3)). IP(3) decreased the mean close time markedly, but had no effect on the amplitude of BK channels. The activation of IP(3) on BK channels did not decline. The metabolite of IP(3) had no obvious effect on BK channels. This study provides evidence that IP(3) activates BK channels in porcine coronary artery smooth muscle cells in a dose-dependence manner.
Animals ; Coronary Vessels ; cytology ; metabolism ; Inositol 1,4,5-Trisphosphate ; physiology ; Large-Conductance Calcium-Activated Potassium Channels ; metabolism ; Muscle, Smooth, Vascular ; metabolism ; Swine ; Vasodilation ; physiology

OBJECTIVETo compare the effects of instant electroacupuncture (EA) at the different acupoints on IP3 in the uterus tissue of dysmenorrhea model rats so as to investigate the specificity of acupoints.

METHODSFifty female SD rats were randomly divided into a saline group, a model group, a Sanyinjiao (SF 6) group, a Xuehai (SP 10) group and a Hegu (LI 4) group, 10 rats in each group. The rats were given subcutaneous injection of Estradiol Beozoate injection for 10 consecutive days except those in the saline group, and intraperitoneal injection of 2U Oxytocin at 1 h after the last administration to create the dysmenorrhea rats model, and the saline group was given the same dose of saline every day. On the 10th day the rats in each EA group were given EA 20 min, and the rats in the saline group and model group were bound 20 min, and the writhing response was observed at the same time. The uterine IP3 contents were detected with enzyme-linked immunosorbent assay method.

RESULTS(1) Compared with (0.311+/- 0.253) in the saline group, the writhing scores per minute of (5.867 +/- 3.442) in the model group and (2.311 +/- 0.957) in the Xuehai (SP 10) group were both increased significantly (P < 0.01, P < 0.05), and (1.833 +/- 1.355) in the Sanyinjiao (SP 6) group and (0.743 +/- 0.306) in the Hegu (LI 4) group showed no significant differences (P > 0.05). Compared with that in the model group, the writhing scores per minute decreased significantly (all P < 0.01) in all the EA groups, with no significant differences among all the EA groups (all P > 0.05). (2) Compared with (2.698 +/- 1.491) ng/mg in the saline group, IP3 contents of the uterus of (0.813 +/- 0.899) ng/mg in the model group, (1.740 +/- 0.375) ng/mg in the Sanyinjiao (SP 6) group and (0.692 +/- 0.212) ng/mg in the Hegu (LI 4) group were all lower significantly (P < 0.05, P < 0.01), and (0.743+/- 0.306) ng/mg in the Xuehai (SP 10) group showed no significant differences (P > 0.05). Compared with that in the model group, IP3 content of the uterus in the Hegu (LI 4) group showed no significant difference (P > 0.05), and those in the Sanyinjiao (SP 6) group and in the Xuehai (SP 10) group increased significantly (both P < 0 05), which were significantly higher than that in the Hegu (II 4) group (P < 0.05, P < 0.01).

CONCLUSIONThere are no significant differences among the instant EA groups in improving the dysmenorrhea symptoms, but there is obvious specificity of acupoint effects in the regulation of IP3. Electroacupuncture at "Sanyinjiao (SP 6) " Xuehai (SP 10)" has more marked effect in dysmenorrhea model rats.

Acupuncture Points ; Animals ; Disease Models, Animal ; Dysmenorrhea ; metabolism ; therapy ; Electroacupuncture ; Female ; Humans ; Inositol 1,4,5-Trisphosphate ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Uterus ; metabolism

The acrosome reaction is a prerequisite for fertilization, and its signaling pathway has been investigated for decades. Regardless of the type of inducers present, the acrosome reaction is ultimately mediated by the elevation of cytosolic calcium. Inositol 1,4,5-trisphosphate-gated calcium channels are important components of the acrosome reaction signaling pathway and have been confirmed by several researchers. In this study, we used a novel permeabilization tool BioPORTER^® and first demonstrated its effectiveness in spermatozoa. The inositol 1,4,5-trisphosphate type-1 receptor antibody was introduced into spermatozoa by BioPORTER^® and significantly reduced the calcium influx and acrosome reaction induced by progesterone, solubilized zona pellucida, and the calcium ionophore A23187. This finding indicates that the inositol 1,4,5-trisphosphate type-1 receptor antibody is a valid inositol 1,4,5-trisphosphate receptor inhibitor and provides evidence of inositol 1,4,5-trisphosphate-gated calcium channel involvement in the acrosome reaction in human spermatozoa. Moreover, we demonstrated that the transfer of 1,4,5-trisphosphate into spermatozoa induced acrosome reactions, which provides more reliable evidence for this process. In addition, by treating the spermatozoa with inositol 1,4,5-trisphosphate/BioPORTER^® in the presence or absence of calcium in the culture medium, we showed that the opening of inositol 1,4,5-trisphosphate-gated calcium channels led to extracellular calcium influx. This particular extracellular calcium influx may be the major process of the final step of the acrosome reaction signaling pathway.
Acrosome Reaction/physiology* ; Calcimycin/pharmacology* ; Calcium/pharmacology* ; Calcium Ionophores/pharmacology* ; Drug Delivery Systems ; Humans ; Inositol 1,4,5-Trisphosphate Receptors/metabolism* ; Male ; Progesterone/pharmacology* ; Spermatozoa/metabolism* ; Zona Pellucida/metabolism*

OBJECTIVETo study the changes of expression of type I inositol 1,4,5 triphosphate receptors (IP3RI) in the kidneys of mice with fulminant hepatic failure (FHF) in order to understand the role renal vasoconstriction plays in the development of hepatorenal syndrome (HRS).

METHODSOne hundred twenty male Balb/c mice were divided into 4 groups. In the fourth group (60 mice) lipopolysaccharide with D-galactosamine was injected intraperitoneally to induce acute liver necrosis. The first-third groups (20 mice in each group) served as controls and those mice were given NS, LPS or GalN intraperitoneally. At the end of 2 h, 6 h, and 9 h, mice were sacrificed and their livers and kidneys were removed and examined histologically. Immunohistochemistry, Western blot and reverse transcription PCR (RT-PCR) were used to detect the distribution and expression of IP3RI in the kidneys.

RESULTSIP3RI protein was localized in the cytoplasma of glomerular mesangial cells and vascular smooth muscle cells in the kidneys. In the kidney tissues from mice with FHF at 6 h and 9 h, IP3RI-positive staining cells increased significantly (6 h: chi(2)=7.11, P less than 0.01; 9 h: (chi)2=9.15, P less than 0.01). Western blot demonstrated a consistent and significant increase of IP3RI expression in mice with FHF at 6 h and 9 h (6 h: t=3.16, P less than 0.05; 9 h: t=5.43, P less than 0.01). Using RT-PCR we observed that IP3RI mRNA in FHF samples at 2 h, 6 h and 9 h was markedly up-regulated in comparison to that of the controls (2 h: t=2.47, P less than 0.05; 6 h: t=4.42, P less than 0.01; 9 h: t=2.16, P less than 0.05).

CONCLUSIONThe expression of IP3RI protein increased in glomerular mesangial cells and renal vascular smooth muscle cells of FHF mice. Perhaps this was caused by IP3RI mRNA up-regulation.

Animals ; Disease Models, Animal ; Inositol 1,4,5-Trisphosphate Receptors ; metabolism ; Liver Failure, Acute ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; RNA, Messenger ; genetics

OBJECTIVETo investigate the effect of second messengers protein kinase C (PKC) and inositol (1,4,5)-trisphosphate (IP(3)) during hypoxic-ischemic brain injury in neonatal rats.

METHODSThe protein concentration was determined by Lowry's method. PKC activity was measured by the incorporation of [gamma-32P] into a specific substrate peptide in the cytosol and particulate fraction, respectively. IP(3) was determined by the radioreceptor binding assay.

RESULTSCompared with the control, PKC activities in the particulate fractions in both the cerebral cortex and hippocampus decreased, while increased in the cytosol in cerebral cortex and remained within the normal range in the cytosol in the hippocampus at 0, 4, 12, 24, 48, 72 h, 7, and 14 d after hypoxic-ischemia for 20 min. All these changes restored to normal levels at 21 d post hypoxic-ischemia. Similarly, a decrease in IP(3) in the cerebral cortex and hippocampus and an increase in IP(3) in the thalamus after hypoxic-ischemia were noted, respectively. Changes in cytosolic PKC activity were not related to those of IP(3), as evaluated statistically.

CONCLUSIONHypoxia-ischemia induces disturbance of the second messengers IP(3) and PKC, which may play important roles in the pathogenesis of hypoxic-ischemic brain injury.

Animals ; Animals, Newborn ; Brain Ischemia ; etiology ; metabolism ; Female ; Hypoxia, Brain ; etiology ; metabolism ; Inositol 1,4,5-Trisphosphate ; physiology ; Male ; Protein Kinase C ; physiology ; Rats ; Rats, Wistar

The purpose of the present study was to determine the role of inositol 1,4,5-trisphosphate receptor 3 (IP₃R3) in renal cyst development in autosomal dominant polycystic kidney disease (ADPKD). 2-aminoethoxy-diphenyl borate (2-APB) and shRNA were used to suppress the expression of IP₃R3. The effect of IP₃R3 on cyst growth was investigated in Madin-Darby canine kidney (MDCK) cyst model, embryonic kidney cyst model and kidney specific Pkd1 knockout (PKD) mouse model. The underlying mechanism of IP₃R3 in promoting renal cyst development was investigated by Western blot and immunofluorescence staining. The results showed that the expression level of IP₃R3 was significantly increased in the kidneys of PKD mice. Inhibiting IP₃R3 by 2-APB or shRNA significantly retarded cyst expansion in MDCK cyst model and embryonic kidney cyst model. Western blot and immunofluorescence staining results showed that hyperactivated cAMP-PKA signaling pathway in the growth process of ADPKD cyst promoted the expression of IP₃R3, which was accompanied by a subcellular redistribution process in which IP₃R3 was translocated from endoplasmic reticulum to intercellular junction. The abnormal expression and subcellular localization of IP₃R3 further promoted cyst epithelial cell proliferation by activating MAPK and mTOR signaling pathways and accelerating cell cycle. These results suggest that the expression and subcellular distribution of IP₃R3 are involved in promoting renal cyst development, which implies IP₃R3 as a potential therapeutic target of ADPKD.
Animals ; Dogs ; Mice ; Cysts/genetics* ; Inositol 1,4,5-Trisphosphate Receptors/pharmacology* ; Kidney/metabolism* ; Polycystic Kidney Diseases/metabolism* ; Polycystic Kidney, Autosomal Dominant/drug therapy* ; Madin Darby Canine Kidney Cells

Previous studies have indicated that ERp44 inhibits inositol 1,4,5-trisphosphate (IP(3))-induced Ca(2+) release (IICR) via IP(3)R(1), but the mechanism remains largely unexplored. Using extracellular ATP to induce intracellular calcium transient as an IICR model, Ca(2+) image, pull down assay, and Western blotting experiments were carried out in the present study. We found that extracellular ATP induced calcium transient via IP(3)Rs (IICR) and the IICR were markedly decreased in ERp44 overexpressed Hela cells. The inhibitory effect of C160S/C212S but not C29S/T396A/ΔT(331-377) mutants of ERp44 on IICR were significantly decreased compared with ERp44. However, the binding capacity of ERp44 to L3V domain of IP(3)R(1) (1L3V) was enhanced by ERp44 C160S/C212S mutation. Taken together, these results suggest that the mutants of ERp44, C160/C212, can more tightly bind to IP(3)R(1) but exhibit a weak inhibition of IP(3)R(1) channel activity in Hela cells.
Adenosine Triphosphate ; pharmacology ; Amino Acid Substitution ; Biological Transport ; drug effects ; physiology ; Blotting, Western ; Calcium ; metabolism ; Calcium Signaling ; drug effects ; physiology ; HeLa Cells ; Humans ; Immunoprecipitation ; Inositol 1,4,5-Trisphosphate ; metabolism ; Inositol 1,4,5-Trisphosphate Receptors ; physiology ; Membrane Potentials ; drug effects ; physiology ; Membrane Proteins ; genetics ; metabolism ; Microscopy, Confocal ; Molecular Chaperones ; genetics ; metabolism ; Mutation ; Plasmids ; Transfection