Uranyl acetate modulates gene expression and protein levels of the type 2, but not type 1 inositol 1,4,5-trisphosphate receptors in mouse kidney

Nephrotoxic effect of uranium is already well documented. Nevertheless, little is known about the effect of uranium on calcium homeostasis and calcium transport systems. Calcium released from endoplasmic reticulum through special calcium release channels--inositol 1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs)--serves as a main source of cytosolic calcium signaling in the majority of cell types. To contribute to understanding mechanism of toxicity of the uranyl acetate (UA), we focused on modulation of the gene expression, protein levels and activity of IP3 receptor's intracellular calcium channels by UA in mouse kidney. We have found that UA did not affect mRNA and protein levels of the type 1 IP3Rs, but increased mRNA and also protein levels of the type 2 IP3 receptors in kidney. Nevertheless, IP3-induced calcium release was decreased by addition of UA. We assume that decreased activity of IP3 receptors due to the acute exposure to UA results in feedback, which triggers activation of IP3R2 expression. Thus, inhibition of calcium release and increased levels of the type 2 IP3 receptors might participate, at least partially, in UA-induced nephrotoxicity.     

Distribution of neuronal and non-neuronal spliced variants of type 1 IP(3)-receptor in rat hypothalamus and brain stem

In the nervous system, inositol 1,4,5-trisphosphate (IP(3)) is one of the second messengers produced by PI hydrolysis and triggers IP(3)-receptor (IP(3)R) mediated calcium release from intracellular pools. Throughout the brain, the type 1 IP(3)R is predominantly expressed and its mRNA is widely distributed. Alternative splicing of IP(3)R1 (SI and SII) occurs in two distinct regions. SI splicing in the middle of the ligand binding domain may alter the IP(3) binding activity, while SII splicing probably affects the protein kinase A phosphorylation sites and kinetics. Selective use of IP(3)-receptor subtypes may permit a tissue specific and developmentally specific expression of functionally distinct channels.The present work was focused on detection of the alternatively spliced mRNA of type 1 IP(3)-receptor in individual brain structures and nuclei. Using RT-PCR we detected neuronal (535bp) and non-neuronal (410bp) forms. We identified both spliced variants in the majority of brain structures, except in the cerebellum and medulla. In the cerebellum, the neuronal form of type 1 IP(3)R was found exclusively, while in the medulla, the non-neuronal form was much more abundant. Nevertheless, Western blot analysis and hybridization with specific antibody against IP(3)R revealed no qualitative, but only quantitative differences. Similarly, IP(3) dependent calcium release did not show any differences between the cerebellum and pons. These results demonstrate the distribution of alternatively spliced S2 variants of type 1 IP(3)R in selected brain structures and nuclei. The physiological relevance of these two forms remains to be elucidated by further studies.     

Repeated immobilization stress reduces the gene expression of the type 1 and 2 IP3 receptors in stellate ganglia

Inositol 1,4,5-trisphosphate (IP(3)) is one of the second messengers produced by phosphoinositid hydrolysis and triggers IP(3) receptor (IP(3)R) mediated calcium release from intracellular pools. To determine whether immobilization stress affects the gene expression and protein level of IP(3)R in stellate ganglia, animals were immobilized once for 2h and/or for 7 days, 2h daily. After decapitation, stellate ganglia were extirpated and the gene expression of IP(3) receptors was evaluated. Protein levels of IP(3) receptor were measured by Western blot analysis using the antibody against IP(3) receptor. In the present work, we clearly show that type 1 and 2 IP(3) receptors, but not the type 3 IP(3) receptor, are expressed in stellate ganglia. Both types, type 1 and 2 IP(3) receptors, are not significantly affected by single 2h immobilization stress on mRNA and protein level. However, gene expression of both these types is significantly reduced by repeated immobilization stress for 7 days, 2h daily. The IP(3) receptor protein is reduced as well. Physiological relevance of our observations remains to be elucidated.     

Adrenergic modulation of the type 1 IP3 receptors in the rat heart

Inositol 1,4,5-trisphosphate (IP3) receptors are calcium-releasing channels localized on the sarcoplasmic reticulum. IP3 receptors mediate the calcium mobilizing effect of a wide range of hormones, cytokines, and neurotransmitters and play an important role in variety of cell functions. The aim of this work was to study, how partial depletion of catecholamines affects the gene expression and protein levels of the type 1 IP3 receptors in rat heart. The type 1 IP3 receptor mRNA levels were studied in the left cardiac atrium and ventricle of rats treated with 6-hydroxydopamine (6-OHDA) in control and stressed conditions. The 6-OHDA produces anatomical and functional denervation resulting in decreased levels of noradrenaline and adrenaline. We also used corticoliberin (CRH) knockout mice, where secretion of adrenaline is significantly suppressed. Administration of 6-OHDA significantly decreases mRNA levels of the type 1 IP3 receptor in both, the left atrium and the left ventricle, while the gene expression of the sarcoplasmic reticular Ca2+-ATPase (SERCA 2) was unaffected. CRH knockout mice possess markedly lower levels of the type 1 IP3 receptor mRNA compared to wild-type mice in both, control and stressed conditions. These data point to the adrenergic modulation of the type 1 IP3 receptors in the rat hearts.     

Effect of two distinct stressors on gene expression of the type 1 IP3 receptors

Inositol 1,4,5-trisphosphate (IP3) is one of the second messengers, which triggers calcium release from intracellular pools via IP3 receptors. Previously we have shown that single immobilization stress increased gene expression of both, the type 1 and type 2 IP3 receptors (IP3R1 and IP3R2, respectively). In this study we evaluated whether long-term exposure to softer stressor (cold exposure to 4 degrees C) can affect the response to single immobilization stress. We examined modulation of the type 1 IP3 receptor gene expression by each stressor separately, and then in their combination. Rats were immobilized for 30 min and 120 min and were decapitated immediately or 3 h after immobilization. Cold stress was performed by exposure of animals to 4 degrees C temperature for 1, 7 and 28 days. To determine the effect of both stressors in combination, animals exposed to cold for 28 days were afterwards exposed to immobilization for 120 min and decapitated 3 h after the end of stressful stimulus. Our results verify that single immobilization increases the IP3R1 gene expression in left atria of rat heart, while cold stress elevates the level of gene expression only after the exposure to cold for 7 days. The exposure to cold for 28 days did not increase the gene expression of the type 1 IP3 receptor compared to control. Application of both stressors (28 days of cold exposure followed by 120 min of immobilization with subsequent 3 h rest) showed the tendency of increased IP3R1 gene expression compared to absolute, nonstressed control, but level of the type 1 IP3 receptor mRNA was significantly lower compared to mRNA levels of solely immobilized animals. Thus, cold exposure affects the response of the gene expression of the type 1 IP3 receptor to immobilization stress.     

Immobilization stress elevates IP(3) receptor mRNA in adult rat hearts in a glucocorticoid-dependent manner

Gene expression of the type 1 and 2 inositol 1,4,5-trisphosphate (IP(3)) receptors in the rat cardiac atria and ventricles and their possible modulation by single immobilization stress was studied. Single immobilization stress significantly elevated mRNA levels for both types of these receptors. To evaluate the involvement of glucocorticoids in the modulation of the gene expression of IP(3) receptors by immobilization stress, we used adrenalectomized and/or hypophysectomized rats. Since adrenalectomy and/or hypophysectomy completely abolished increase in IP(3) receptor's mRNA levels after the immobilization, we conclude that immobilization stress elevates mRNA of type 1 and 2 IP(3) receptors, mainly through the glucocorticoid responsive element.     

trkB-Receptor Activation Contributes to the Kainate-Induced Increase in BDNF mRNA Synthesis

1. The expression of brain-derived neurotrophic factor (BDNF) mRNA is induced by neuronal activity through increased intracellular calcium. As BDNF also increases intracellular calcium levels through trkB activation, we have examined here whether BDNF also regulates the synthesis of its own mRNA.2. Neurotrophin mRNA expression was induced with kainic acid administration in transgenic mice overexpressing the dominant-negative form of BDNF receptor trkB and wild-type littermates.3. Kainate strongly induced BDNF mRNA expression in both genotypes, but the upregulation was significantly lower in transgenic mice.4. These data suggest that the synthesis of BDNF mRNA is at least partly mediated by BDNF release and the activation of trkB receptors. The present findings further suggest that the BDNF signaling system in brain is regulated by positive feedback.     

Inositol 1,4,5-trisphosphate receptor expression in cardiac myocytes

Calcium release from intracellular stores is the signal generated by numerous regulatory pathways including those mediated by hormones, neurotransmitters and electrical activation of muscle. Recently two forms of intracellular calcium release channels (CRCs) have been identified. One, the inositol 1,4,5-trisphosphate receptors (IP3Rs) mediate IP3-induced Ca2+ release and are believed to be present on the ER of most cell types. A second form, the ryanodine receptors (RYRs) of the sarcoplasmic reticulum, have evolved specialized functions relevant to muscle contraction and are the major CRCs found in striated muscles. Though structurally related, IP3Rs and RYRs have distinct physiologic and pharmacologic profiles. In the heart, where the dominant mechanism of intracellular calcium release during excitation-contraction coupling is Ca(2+)-induced Ca2+ release via the RYR, a role for IP3-mediated Ca2+ release has also been proposed. It has been assumed that IP3Rs are expressed in the heart as in most other tissues, however, it has not been possible to state whether cardiac IP3Rs were present in cardiac myocytes (which already express abundant amounts of RYR) or only in non- muscle cells within the heart. This lack of information regarding the expression and structure of an IP3R within cardiac myocytes has hampered the elucidation of the significance of IP3 signaling in the heart. In the present study we have used combined in situ hybridization to IP3R mRNA and immunocytochemistry to demonstrate that, in addition to the RYR, an IP3R is also expressed in rat cardiac myocytes. Immunoreactivity and RNAse protection have shown that the IP3R expressed in cardiac myocytes is structurally similar to the IP3R in brain and vascular smooth muscle. Within cardiac myocytes, IP3R mRNA levels were approximately 50-fold lower than that of the cardiac RYR mRNA. Identification of an IP3R in cardiac myocytes provides the basis for future studies designed to elucidate its functional role both as a mediator of pharmacologic and hormonal influences on the heart, and in terms of its possible interaction with the RYR during excitation- contraction coupling in the heart.     

Haloperidol increases expression of the inositol 1,4,5-trisphosphate receptors in rat cardiac atria, but not in ventricles

Numerous ligands of sigma receptors are known to prolong the QT interval and therefore cause a variety of arrhythmias. High affinity binding sites for the prototypical sigma ligand haloperidol were found in membranes of cardiac myocytes from adult rats. Activation of sigma 1 receptor leads to a release of calcium from the endoplasmic reticulum that follows increased synthesis of inositol 1,4,5-trisphosphate (IP3). We studied the effect of long-term haloperidol treatment on the expression of sigma 1 receptors, IP3 receptors of type 1 and 2 in the individual parts of the rat heart, in isolated rat cardiomyocytes and in PC12 cells. We have found that prolonged treatment with haloperidol significantly increased mRNA levels of sigma 1 receptors in both atria and ventricles. Sigma 1 receptor's mRNA was increased also in isolated cardiomyocytes. Haloperidol treatment affects the expression of IP3 receptors of type 1 and 2 in cardiac atria, but not in cardiac ventricles. We observed increase in IP3 receptors in differentiated PC12 cells, but not in isolated cardiomyocytes. We propose that this increase might participate in triggering cardiac arrhythmias during haloperidol treatment, which has to be further verified.     

Molecular cloning and characterization of two novel retinoic acid-inducible orphan G-protein-coupled receptors (GPRC5B and GPRC5C)

Using homology searching of public databases with a metabotropic glutamate receptor sequence from Caenorhabditis elegans, two novel protein sequences (named RAIG-2 (HGMW-approved symbol GPRC5B) and RAIG-3 (HGMW-approved symbol GPRC5C) were identified containing seven putative transmembrane domains characteristic of G-protein-coupled receptors (GPCRs). RAIG-2 and RAIG-3 encode open reading frames of 403 and 442 amino acid polypeptides, respectively, and show 58% similarity to the recently identified retinoic acid-inducible gene-1 (RAIG-1, HGMW-approved symbol RAI3). Analysis of the three protein sequences places them within the type 3 GPCR family, which includes metabotropic glutamate receptors, GABA(B) receptors, calcium-sensing receptors, and pheromone receptors. However, in contrast to other type 3 GPCRs, RAIG-1, RAIG-2, and RAIG-3 have only short N-terminal domains. RAIG-2 and RAIG-3 cDNA sequences were cloned into the mammalian expression vector pcDNA3 with c-myc or HA epitope tags inserted at their N-termini, respectively. Transient transfection experiments in HEK239T cells using these constructs demonstrated RAIG-2 and RAIG-3 expression at the cell surface. Distribution profiles of mRNA expression obtained by semiquantitative Taq-Man PCR analysis showed RAIG-2 to be predominantly expressed in human brain areas and RAIG-3 to be predominantly expressed in peripheral tissues. In addition, expression of RAIG-2 and RAIG-3 mRNA was increased following treatment with all-trans-retinoic acid in a manner similar to that previously described for RAIG-1. Finally, RAIG-2 was mapped to chromosome 16p12 (D16S405-D16S3045) and RAIG-3 to chromosome 17q25 (D17S1352-D17S785). These results suggest that RAIG-1, RAIG-2, and RAIG-3 represent a novel family of retinoic acid-inducible receptors, most closely related to the type 3 GPCR subfamily, and provide further evidence for a linkage between retinoic acid and G-protein-coupled receptor signal transduction pathways.     

Postnatal expression of the inositol 1,4,5-trisphosphate receptor in canine cerebellum.

1. Inositol 1,4,5-trisphosphate (IP3), an intracellular second messenger, has been shown to be the link between activation of several plasma membrane receptors and Ca2+ release from intracellular, membrane-bound compartments. In this study, the postnatal expression of the canine cerebellum IP3 receptor was investigated by biochemical, ligand binding and immunocytochemical methods. 2. Specific receptor sites for IP3 and the extent of IP3-induced Ca2+ release were quantitated in microsomal fractions isolated from cerebella of developing (0-28 day-old) and adult dogs. The IP3 receptor was detected in newborn animals and adult levels were attained within 3-4 weeks. 3. The time-course of IP3 receptor ontogeny paralleled both growth of Purkinje neurons, as indicated by immunofluorescence of cerebellum cortex cryosections with anti-IP3 receptor antibodies, and synaptogenesis, as judged by Western blotting of the microsomal fractions with anti-synaptophysin antibodies.     

Angiotensin and calcium signaling in the pituitary and hypothalamus

1) In the rat pituitary, angiotensin type 1B receptors (AT_1B) are located in lactotrophs and corticotrophs.2) Activation of AT_1B receptors are coupled to G_q/11 (Guanine protein coupled receptor, or GPCR); they increase phospholipase C (PLC) activity resulting in inositol 1,4,5 triphosphate (InsP₃) and diacylglycerol (DAG) formation. A biphasic increase in [Ca²⁺]_itriggered by InsP₃ and DAG ensues.3) As many GPCRs, AT_1B pituitary receptors rapidly desensitize.4) This was observed in the generation of InsP3, the mobilization of intracellular Ca²⁺, and in prolactin release. Both homologous and heterologous desensitization was evidenced.5) Desensitization of the angiotensin II type 1 (AT1) receptor in the pituitary shares similarities and differences with endogenously expressed or transfected AT1 receptors in different cell types.6) In the pituitary hyperplasia generated by chronic estrogen treatment there was desensitization or alteration in angiotensin II (Ang II) evoked intracellular Ca²⁺ increase, InsP3 generation, and prolactin release. This correlates with a downregulation of AT1 receptors.7) In particular, in hyperplastic cells Ang II failed to evoke a transient acute peak in [Ca²⁺]_i, which was replaced by a persistent plateau phase of [Ca²⁺]_i increase.8) Different calcium channels participate in Ang II induced [Ca²⁺]_i increase in control and hyperplastic cells. While spike phase in control cells is dependent on intracellular stores sensitive to thapsigargin, in hyperplastic cells plateau increase is dependent on extracellular calcium influx.9) Signal transduction of the AT1 pituitary receptor is greatly modified by hyperplasia, and it may be an important mechanism in the control of the hyperplastic process.10) In the hypothalamus and brain stem there is a predominant expression of AT_1A and AT₂ mRNA.11) Ang II acts at specific receptors located on neurons in the hypothalamus and brain stem to elicit alterations in blood pressure, fluid intake, and hormone secretion.12) Calcium channels play important roles in the Ang II induced behavioral and endocrine responses.13) Ang II, in physiological concentrations, can activate AT1 receptors to stimulate both Ca²⁺ release from intracellular stores and Ca²⁺ influx from the extracellular space to increase [Ca²⁺]_i in polygonal and stellate astroglia of the hypothalamus and brain stem.14) In primary cell culture of neurons from newborn rat hypothalamus and brain stem, it has also been determined that Ang II elicits an AT1 receptor mediated inhibition of delayed rectifier K(+) current and a stimulation of Ca²⁺ current.15) In primary cell cultures derived from the subfornical organ or the organum vasculosum laminae terminalis of newborn rat pups, Ang II produced a pronounced desensitization of the [Ca²⁺]_i response.16) Hypothalamic and pituitary Ang II systems are involved in different functions, some of which are related. At both levels Ang II signals through [Ca²⁺]_i in a characteristic way.     

Studies on thyrotropin releasing hormone in cerebellar ataxia mutant mouse brain

The effects of cathecholamine on the regional TRH distribution in the brain was studied in rolling mouse Nagoya (RMN) and non-affected C3H mice. TRH was extracted from the hypothalamus, brain stem, cerebellum, and cerebrum one hour after i.p. injection of the precursor or inhibitors of cathecholamine. TRH was distributed throughout the brain of both affected and non-affected mice; however, in RMN, TRH levels were lower in the hypothalamus and higher in other areas. 1-Dopa caused a decrease of TRH in the brain stem but no change in other regions in the RMN brain, whereas it caused an increase in TRH levels in all areas of the C3H brain. Fusaric acid increased TRH in the hypothalamus of RMN and decreased it in the cerebellum; alpha-MPT also caused a decrease in the TRH level in the cerebellum. Reserpine increased the TRH level in the hypothalamus and decreased it in the cerebrum. From these results, it appears that cerebellar ataxia in RMN does not result from a decrease in the TRH, which is actually increased in the cerebellum. Catecholamine had different effects on TRH levels in RMN and the controls; this might be due to the excess accumulation of noradrenaline in the RMN brain.     

Effect of iron and retinoic acid on the control of transferrin receptor and ferritin in the human promonocytic cell line U937.

The effect of changes in iron availability and induction of differentiation on transferrin receptor expression and ferritin levels has been examined in the promonocytic cell line U937. Addition of iron (as 200 micrograms/ml saturated transferrin) or retinoic acid (1 microM) both caused approx. 70% reduction in the average number of surface transferrin receptors, while the iron chelator desferrioxamine caused an 84% increase. Comparable changes also occurred in the levels of transferrin receptor mRNA. Neither iron nor retinoic acid significantly altered the half-life of transferrin receptor mRNA in the presence of actinomycin D (approx. 75 min) but a 10-fold increase in stability occurred in the presence of desferrioxamine. Iron and retinoic acid both caused an increase in intracellular ferritin levels (approx. 4-and 3-fold, respectively), while desferrioxamine reduced ferritin levels by approx. two-thirds. The effect of iron and retinoic acid added together did not differ greatly from that of each agent alone. None of the treatments greatly affected levels of L-ferritin mRNA. Virtually no H-ferritin mRNA was detected in U937 cells. These results show that changes in ferritin and transferrin receptor caused by treatment with retinoic acid are similar to those induced by excess iron, and suggest that changes in these proteins during cell differentiation are due to redistribution of intracellular iron into the regulatory pool(s), rather than to iron-independent mechanisms.     

正常猕猴与树鼩神经系统和免疫系统组织中大麻素与阿片受体的表达

为应用猕猴和树鼩动物模型研究毒品成瘾对神经/免疫系统的影响提供基础数据,对大麻素及阿片受体在正常猕猴和树鼩神经系统和免疫系统的表达进行初步确定.采集正常猕猴和树鼩新鲜组织(皮质、小脑、脑干、海马、脊髓、脾脏),应用半定量逆转录PCR和实时定量PCR的方法检测大麻素与阿片受体mRNA在猕猴和树鼩各组织中的表达情况.猕猴脑部各区包括脾脏均表达大麻索受体1(CNR1),而大麻素受体2(CNR2)只表达于脾脏内.三类阿片受体中,mu(μ)受体表达最为广泛,在以上各组织中均有表达;delta(δ)受体表达的组织最少,只在海马表达;kappa(κ)受体表达介于两者之间,分别在皮质、小脑、脑干、脊髓中表达.在树鼩组织中,CNR1和CNR2表达于整个大脑重要脑区中,且CNR1表达量高于同一区域内CNR2表达的鼍:脾脏中CNR2的表达较高,而CNR1不表达.三类阿片受体只有检测到μ受体在脑部与脾脏表达,且在各个脑区的表达量明显高于脾脏的表达量;δ体和κ受体在被检各个组织中均无表达.总体而言,两种大麻素受体在猕猴和树鼩体内表达情况与人类和鼠的情况类似,而三类阿片受体在猕猴体内表达情况与人类吏为接近.猕猴和树鼩可能可用于人类毒品成瘾的研究;猕猴在某些神经受体的表达更接近人类,其在研究毒品成瘾的机理和对免疫系统的影响方面仍有不可替代的地位.     

Expression and signaling of group I metabotropic glutamate receptors in astrocytes and microglia

Stimulation of astrocytes with the excitatory neurotransmitter glutamate leads to the formation of inositol 1,4,5-trisphosphate and the subsequent increase of intracellular calcium content. Astrocytes express both ionotropic receptors and metabotropic glutamate (mGlu) receptors, of which mGlu5 receptors are probably involved in glutamate-induced calcium signaling. The mGlu5 receptor occurs as two splice variants, mGlu5a and mGlu5b, but it was hitherto unknown which splice variant is responsible for the glutamate-induced effects in astrocytes. We report here that both mRNAs encoding mGlu5 receptor splice variants are expressed by cultured astrocytes. The expression of mGlu5a receptor mRNA is much stronger than that of mGlu5b receptor mRNA in these cells. In situ hybridization experiments reveal neuronal expression of mGlu5b receptor mRNA in adult rat forebrain but a strong neuronal expression of mGlu5a mRNA only in olfactory bulb. Signals for mGlu5a receptor mRNA in the rest of the brain were diffuse and weak but consistently above background. Activation of mGlu5 receptors in astrocytes yields increases in inositol phosphate production and transient calcium responses. It is surprising that the rank order of agonist potency [quisqualate > (2S,1 'S,2'S)-2-(carboxycyclopropyl)glycine = trans-(1S,3R)-1-amino-1,3-cyclopentanedicarboxylic acid (1S,3R-ACPD) > glutamate] differs from that reported for recombinantly expressed mGlu5a receptors. The expression of mGlu5a receptor mRNA and the occurrence of 1S,3R-ACPD-induced calcium signaling were found also in cultured microglia, indicating for the first time expression of mGlu5a receptors in these macrophage-like cells.     

Regional Distribution and Relative Abundance of Serotonin2c Receptors in Human Brain: Effect of Suicide

Abnormalities in serotonin receptor subtypes have been observed in the postmortem brain of suicide victims. We examined the regional distribution of serotonin (5HT)(2C) receptor mRNA in several areas of the human brain and also compared its protein and mRNA expression in the prefrontal cortex (PFC), hippocampus, and choroid plexus between suicide victims and normal control subjects. 5HT(2C) receptors were found to be distributed in several areas of the human brain (in order of abundance): highly concentrated and richest in choroid plexus; hypothalamus; nucleus accumbens; with the lowest abundance in PFC and cerebellum. Comparison of 5HT(2C) receptors between suicide victims and control subjects showed higher protein levels in the PFC but not the hippocampus or choroid plexus of suicide victims. However, there were no significant differences in mRNA levels between suicide victims and control subjects in these brain areas. These results suggest that 5HT(2C) receptors are richly distributed throughout the brain with the highest level in the choroid plexus and that abnormalities in protein expression of 5HT(2C) receptors in the PFC may be associated with suicide.     

Dopamine D1 receptors regulate type 1 inositol 1,4,5-trisphosphate receptor expression via both AP-1- and NFATc4-mediated transcriptional processes

Although our recent report demonstrates the essential involvement of up-regulation of a regulator of intracellular Ca(2+) concentration, type 1 inositol 1,4,5-trisphosphate receptors (IP(3) Rs-1), mediated via dopamine D1-like receptor (D1DR) stimulation in the cocaine-induced psychological dependence, the exact mechanisms of regulation of IP(3) R-1 expression by D1DRs have not yet been clarified. This study attempted to clarify these mechanisms using mouse cerebral cortical neurons. An agonist for phosphatidylinositide-linked D1DRs, SKF83959, induced dose- and time-dependently IP(3) R-1 protein up-regulation following its mRNA increase without cAMP production. U73122 (a phospholipase C inhibitor), BAPTA-AM (an intracellular calcium chelating reagent), W7 (a calmodulin inhibitor), KN-93 (a calmodulin-dependent protein kinases inhibitor), and FK506 (a calcineurin inhibitor), significantly inhibited the SKF83959-induced IP(3) R-1 up-regulation. Furthermore, immunohistochemical examinations showed that SKF83959 increased expression of both cFos and cJun in nucleus as well as enhanced translocation of both calcineurin and NFATc4 complex to nucleus from cytoplasm. In addition, SKF83959 directly recruited binding of both AP-1 and NFATc4 to IP(3) R-1 promoter region. These results indicate that D1DR activation induces IP(3) R-1 up-regulation via increased translocation of AP-1 as well as NFATc4 in Gαq protein-coupled calcium signaling transduction pathway.