Exploratory, anxiety and spatial memory impairments are dissociated in mice lacking the LPA1 receptor

Lysophosphatidic acid (LPA) is a new, intercellular signalling molecule in the brain that has an important role in adult hippocampal plasticity. Mice lacking the LPA(1) receptor exhibit motor, emotional and cognitive alterations. However, the potential relationship among these concomitant impairments was unclear. Wild-type and maLPA(1)-null mice were tested on the hole-board for habituation and spatial learning. MaLPA(1)-null mice exhibited reduced exploration in a novel context and a defective intersession habituation that also revealed increased anxiety-like behaviour throughout the hole-board testing. In regard to spatial memory, maLPA(1) nulls failed to reach the controls' performance at the end of the reference memory task. Moreover, their defective working memory on the first training day suggested a delayed acquisition of the task's working memory rule, which is also a long term memory component. The temporal interval between trials and the task's difficulty may explain some of the deficits found in these mice. Principal components analysis revealed that alterations found in each behavioural dimension were independent. Therefore, exploratory and emotional impairments did not account for the cognitive deficits that may be attributed to maLPA(1) nulls' hippocampal malfunction.

Socio-economic factors and stage at presentation of head and neck cancer patients in Ottawa, Canada: a logistic regression analysis

To determine if socio-economic status (SES) affects the stage at presentation of head and neck cancer (HNC) patients in Ottawa, Canada. To determine if the method of diagnosis affects the stage at presentation in these patients. We obtained data on SES, method of diagnosis, and stage at presentation for patients presenting to the head and neck cancer clinic at The Ottawa Hospital Regional Cancer Centre (TORCC). We performed a logistic regression analysis using stage at presentation as the dependent variable. We found no statistically significant association between average family income (by postal code) and stage at presentation. We found that oral cancers presented at a later stage compared with other HNCs but that who made the diagnosis was an important factor. Oral cancers diagnosed by a dentist had 3.44 times the odds of being at a later stage than other HNCs (CI 1.01-11.96), but oral cancers diagnosed by other means had 11.42 times the odds of being at a later stage than other HNCs. We found that male patients presented at a later stage than female patients (OR 2.62, CI 1.03-6.63). Finally, former smokers had about 1/3 the odds of presenting at a later stage than current smokers (OR 0.33, CI 0.13-0.84) although nonsmokers were not significantly less likely than current smokers to present later (OR 0.47, CI 0.17-1.32). We found no evidence that in Ottawa, Canada patients of a lower SES with HNC presented at an different stage than patients with higher SES. We found that patients presenting with oral cancers presented at an earlier stage if they were diagnosed by a dentist.

LPA receptors: subtypes and biological actions

Lysophosphatidic acid (LPA) is a small, ubiquitous phospholipid that acts as an extracellular signaling molecule by binding to and activating at least five known G protein-coupled receptors (GPCRs): LPA(1)-LPA(5). They are encoded by distinct genes named LPAR1-LPAR5 in humans and Lpar1-Lpar5 in mice. The biological roles of LPA are diverse and include developmental, physiological, and pathophysiological effects. This diversity is mediated by broad and overlapping expression patterns and multiple downstream signaling pathways activated by cognate LPA receptors. Studies using cloned receptors and genetic knockout mice have been instrumental in uncovering the significance of this signaling system, notably involving basic cellular processes as well as multiple organ systems such as the nervous system. This has further provided valuable proof-of-concept data to support LPA receptors and LPA metabolic enzymes as targets for the treatment of medically important diseases that include neuropsychiatric disorders, neuropathic pain, infertility, cardiovascular disease, inflammation, fibrosis, and cancer.

Progesterone receptor-mediated up-regulation of transthyretin in preimplantation mouse uterus

Transthyretin (TTR), a carrier for thyroxine and retinol, has its messenger RNA (mRNA) expressed in the glandular endometrial epithelium and its protein detected in the glandular endometrial epithelium and the uterine lumen. TTR mRNA is dramatically up-regulated in the preimplantation mouse uterus as well as the P-treated ovariectomized mouse uterus, and in both situations the up-regulation of TTR is blocked by treatment with the P receptor antagonist RU486.

Lysophospholipid receptors LPA1-3 are not required for the inhibitory effects of LPA on mouse retinal growth cones

One of the major requirements in the development of the visual system is axonal guidance of retinal ganglion cells toward correct targets in the brain. A novel class of extracellular lipid signaling molecules, lysophospholipids, may serve as potential axon guidance cues. They signal through cognate G protein-coupled receptors, at least some of which are expressed in the visual system. Here we show that in the mouse visual system, a lysophospholipid known as lysophosphatidic acid (LPA) is inhibitory to retinal neurites in vitro when delivered extracellularly, causing growth cone collapse and neurite retraction. This inhibitory effect of LPA is both active in the nanomolar range and specific compared to the related lysophospholipid, sphingosine 1-phosphate (S1P). Knockout mice lacking three of the five known LPA receptors, LPA_1-3, continue to display retinal growth cone collapse and neurite retraction in response to LPA, demonstrating that these three receptors are not required for these inhibitory effects and indicating the existence of one or more functional LPA receptors expressed on mouse retinal neurites that can mediate neurite retraction.

Prolonged exposure to sphingosine 1-phosphate receptor-1 agonists exacerbates vascular leak, fibrosis, and mortality after lung injury

Sphingosine 1-phosphate (S1P) is a key endogenous regulator of the response to lung injury, maintaining endothelial barrier integrity through interaction with one of its receptors, S1P(1). The short-term administration of S1P or S1P(1) receptor agonists enhances endothelial monolayer barrier function in vitro, and attenuates injury-induced vascular leak in the lung and other organ systems in vivo. Although S1P(1) agonists bind to and activate S1P(1), several of these agents also induce receptor internalization and degradation, and may therefore act as functional antagonists of S1P(1) after extended exposure. Here we report on the effects of prolonged exposure to these agents in bleomycin-induced lung injury. We demonstrate that repeated administration of S1P(1) agonists dramatically worsened lung injury after bleomycin challenge, as manifested by increased vascular leak and mortality. Consistent with these results, prolonged exposure to S1P(1) agonists in vitro eliminated the ability of endothelial cell monolayers to respond appropriately to the barrier-protective effects of S1P, indicating a loss of normal S1P-S1P(1) signaling. As bleomycin-induced lung injury progressed, continued exposure to S1P(1) agonists also resulted in increased pulmonary fibrosis. These data indicate that S1P(1) agonists can act as functional antagonists of S1P(1) on endothelial cells in vivo, which should be considered in developing these agents as therapies for vascular leak syndromes. Our findings also support the hypothesis that vascular leak is an important component of the fibrogenic response to lung injury, and suggest that targeting the S1P-S1P(1) pathway may also be an effective therapeutic strategy for fibrotic lung diseases.

Blockade of sphingosine 1-phosphate receptor 2 signaling attenuates streptozotocin-induced apoptosis of pancreatic beta-cells

Sphingosine 1-phosphate (S1P) is a potent sphingolipid mediator that acts through five cognate G protein-coupled receptors (S1P(1)-S1P(5)) and regulates many critical biological processes. Recent studies indicated that S1P at nanomolar concentrations significantly reduces cytokine-induced apoptosis of pancreatic beta-cells in which genes for S1P(1)-S1P(4) are co-expressed. However, the S1P receptor subtype(s) involved in this effect remains to be clarified. In this study, we investigated the potential role of S1P(2) in streptozotocin (STZ)-induced apoptosis of pancreatic beta-cells and progression of diabetes. S1P(2)-deficient (S1P(2)(-/-)) mice displayed a greater survive ability, lower blood glucose levels, and smaller numbers of TUNEL-positive apoptotic beta-cells to administration of a high dose of STZ than wild-type (WT) mice. S1P(2)(-/-) mice showed higher insulin/glucose ratios (an index of relative insulin deficiency) and larger insulin-positive islet areas to administration of a low dose of STZ than WT mice. Moreover, administration of JTE-013, a S1P(2)-specific antagonist, to WT mice ameliorated STZ-induced blood glucose elevation and reduced the incidence of diabetes. Our findings indicate that blockade of S1P(2) signaling attenuates STZ-induced apoptosis of pancreatic beta-cells and decreases the incidence of diabetes.

Lysophosphatidic acid (LPA) signaling in vertebrate reproduction

Lysophosphatidic acid (LPA) is a cell membrane phospholipid metabolite that can act as an extracellular signal. Its effects are mediated through at least five G protein-coupled receptors, LPA(1-5), and probably others as well. Studies in multiple species including LPAR-deficient mice and humans have identified or implicated important roles for receptor-mediated LPA signaling in multiple aspects of vertebrate reproduction. These include ovarian function, spermatogenesis, fertilization, early embryo development, embryo implantation, embryo spacing, decidualization, pregnancy maintenance and parturition. LPA signaling can also have pathological consequences, influencing aspects of endometriosis and ovarian cancer. Here we review recent progress in LPA signaling research relevant to female and male reproduction.

Cultural Preferences for Chaperone Use during Breast Examinations: A Preliminary Study

Previous studies have demonstrated that use of chaperones by physicians occurs most consistently for pelvic and rectal exams than for breast examinations. Factors that may influence chaperone for breast examination include duration of doctor-patient relationship, gender of the examiner, and availability of an assistant. The purpose of this study is to characterize patient preferences, not previously reported, for chaperone use.A patient questionnaire was approved by the institutional IRB at NYU Langone Medical Center and Bellevue Hospital. It was translated into Chinese, Spanish, and Arabic. Responses were collected from 277 patients. Variables included age, marital status, highest level of education, income, family background, religion, primary language, and chaperone and examiner preferences. For the respondents who preferred a chaperone, education was categorized as some college or none, language was English or non-English-speaking, background was Caucasian or non-Caucasian, and religion was Christian or non-Christian. Descriptive analyses and Pearson's chi-square test was used to determine significance.Median age was 49 years, range 17-87 years. 28 (10%) respondents preferred to have a chaperone present. An equal proportion of respondents did not want a chaperone (N=95, 34%) or had no preference (N=95, 34%). An additional 19% (N=53) of patients indicated that they preferred to be asked about their wishes. 142 (52%) indicated that they preferred a female examiner, 2 (1%) preferred a male examiner, and 126 (46%) had no preference regarding the examiner's gender.Table 1. Respondent Characteristics (N=277)VariablesN (%)EDUCATION (N=256) Grade School10 (4%)High School44 (17%)College116 (45%)Graduate School86 (34%)FAMILY BACKGROUND (N = 251) Caucasian/European159 (64%)African-American18 (7%)Hispanic28 (11%)Middle-Eastern17 (7%)Asian28 (11%)Other1 (0%)RELIGION (N = 250) Christian137 (55%)Jewish, reform49 (20%)Jewish, orthodox16 (6%)Islam14 (5%)Buddhist5 (2%)Other22 (9%)LANGUAGE (N = 256) English198 (77%)Spanish15 (6%)Chinese9 (3%)Arabic12 (5%)Other22 (9%)CHAPERONE PREFERENCE (N = 277) Do not use95 (34%)Use28 (10%)No preference94 (34%)Like to be asked53 (19%)Unknown7 (3%)EXAMINER GENDER PREFERENCE (N = 273) Female142 (52%)Male2 (1%)No preference126 (46%)Unknown3 (1%) Of the 28 patients who did prefer a chaperone, there was a statistically significant difference, p=0.011, for family background that was non-Caucasian. There was no statistical finding for differences in education, religion, or language.Table 2. Characteristics of Respondents who Prefer a Chaperone (N = 28)VARIABLESP-VALUEEducation0.078Language0.409Family Background0.011*Religion0.161* Denotes Statistical SignificanceThe majority of women responding to our survey either did not want a chaperone present for a breast examination or had no preference. However, the majority of all respondents did prefer to have a female examiner. This may simply represent that these patients were comfortable with a woman performing the exam. Additional investigation will further evaluate possible cultural differences.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6080.

Mammographic Density and Lobular Involution in Older Women with Abnormal Breast Imaging

Mammographic density has been established as an independent risk factor for breast cancer, and there is data to suggest that the degree of lobular involution in the breast tissue may also function as an independent risk factor for the disease. The present study was designed to investigate the relationship between mammographic density and lobular involution in a population of mature women undergoing open biopsy for non-palpable breast lesions.A total of 199 women over the age of 60 who underwent breast biopsy with image-guided localization in 2008 at NYU Langone Medical Center formed the study population. Variables of interest included age, breast density, degree of involution, use of hormone replacement therapy (HRT) and biopsy histology (invasive ductal and lobular carcinoma and intraductal carcinoma vs. benign). Breast density was categorized according to BI-RADS classification as less dense (predominantly fatty and scattered fibroglandular elements) vs more dense (heterogeneously dense and extrememely dense). Degree of involution was classified as none (0%), partial (1-74%) and complete (>75%). All specimens were reviewed by a single pathologist who used the criteria of Hartmann, et al in evaluating degree of involution. Statistical analysis was performed using Pearson's Chi-square test and logistic regression analyses.In agreement with our previously presented data, we found an inverse relationship between breast density and age (p=0.02). In our cohort of women over 60 with abnormal breast imaging, we found a trend toward an inverse relationship between age and degree of lobular involution, but this did not achieve statistical significance. 129 of our patients had biopsies yielding malignant histology. There was no significant relationship between degree of lobular involution and biopsy histology. Use of HRT did not correlate with breast density in our cohort. There was no discernable relationship between degree of involution and history of prior or current HRT use.Association of lobular involution with age, density, histology, and HRT  INVOLUTION TOTALP-VALUE NONEPARTIALCOMPLETEN (%) AGE (YRS)      60-696337617 (9%)0.18270-797202959 (29%) 80-894618123 (62%) DENSITY     Less Dense143477125 (63%)0.177More Dense3254674 (37%) HISTOLOGY     Benign5194670 (35%)0.690Malignant124077129 (65%) HRT     Never11246398 (70%)0.774Ever3112741 (30%)  Our study reinforces the general observation that breast density decreases with age. Our data do not permit us to comment on the validity of lobular involution as a risk factor for breast cancer. However, the degree of lobular involution did not predict malignant histology in our cohort. There was a trend toward an inverse relationship between mammographic density and lobular involution. This observation suggests that other factors such as stromal features may be responsible for the increased mammographic density in these older patients. Further study is warranted to better understand the significance of lobular involution and its relationship with mammographic density in all age groups of women undergoing breast cancer screening.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6072.

Role of lysophosphatidic acid receptor LPA2 in the development of allergic airway inflammation in a murine model of asthma

BACKGROUND

Lysophosphatidic acid (LPA) plays a critical role in airway inflammation through G protein-coupled LPA receptors (LPA1-3). We have demonstrated that LPA induced cytokine and lipid mediator release in human bronchial epithelial cells. Here we provide evidence for the role of LPA and LPA receptors in Th2-dominant airway inflammation.

METHODS

Wild type, LPA1 heterozygous knockout mice (LPA1+/-), and LPA2 heterozygous knockout mice (LPA2+/-) were sensitized with inactivated Schistosoma mansoni eggs and local antigenic challenge with Schistosoma mansoni soluble egg Ag (SEA) in the lungs. Bronchoalveolar larvage (BAL) fluids and lung tissues were collected for analysis of inflammatory responses. Further, tracheal epithelial cells were isolated and challenged with LPA.

RESULTS

BAL fluids from Schistosoma mansoni egg-sensitized and challenged wild type mice (4 days of challenge) showed increase of LPA level (approximately 2.8 fold), compared to control mice. LPA2+/- mice, but not LPA1+/- mice, exposed to Schistosoma mansoni egg revealed significantly reduced cell numbers and eosinophils in BAL fluids, compared to challenged wild type mice. Both LPA2+/- and LPA1+/- mice showed decreases in bronchial goblet cells. LPA2+/- mice, but not LPA1+/- mice showed the decreases in prostaglandin E2 (PGE2) and LPA levels in BAL fluids after SEA challenge. The PGE2 production by LPA was reduced in isolated tracheal epithelial cells from LPA2+/- mice. These results suggest that LPA and LPA receptors are involved in Schistosoma mansoni egg-mediated inflammation and further studies are proposed to understand the role of LPA and LPA receptors in the inflammatory process.

Lysophosphatidic acid-3 receptor-mediated feed-forward production of lysophosphatidic acid: an initiator of nerve injury-induced neuropathic pain

BACKGROUND

We previously reported that intrathecal injection of lysophosphatidylcholine (LPC) induced neuropathic pain through activation of the lysophosphatidic acid (LPA)-1 receptor, possibly via conversion to LPA by autotaxin (ATX).

RESULTS

We examined in vivo LPA-induced LPA production using a biological titration assay with B103 cells expressing LPA1 receptors. Intrathecal administration of LPC caused time-related production of LPA in the spinal dorsal horn and dorsal roots, but not in the dorsal root ganglion, spinal nerve or sciatic nerve. LPC-induced LPA production was markedly diminished in ATX heterozygotes, and was abolished in mice that were deficient in LPA3, but not LPA1 or LPA2 receptors. Similar time-related and LPA3 receptor-mediated production of LPA was observed following intrathecal administration of LPA. In an in vitro study using spinal cord slices, LPA-induced LPA production was also mediated by ATX and the LPA3 receptor. Intrathecal administration of LPA, in contrast, induced neuropathic pain, which was abolished in mice deficient in LPA1 or LPA3 receptors.

CONCLUSION

These findings suggest that feed-forward LPA production is involved in LPA-induced neuropathic pain.

Lysophosphatidic acid in vascular development and disease

Lysophosphatidic acid (LPA) is a small signaling lipid that is capable of stimulating a plethora of different cellular responses through the activation of its family of cognate G protein-coupled receptors. LPA mediates a wide range of biological effects in many tissue types that have been recently reviewed; however, its effects on vasculature development and function have received comparatively less examination. In this review, literature on the actions of LPA in three main aspects of vascular development (vasculogenesis, angiogenesis, and vascular maturation) is discussed. In addition, evidence for the roles of LPA signaling in the formation of secondary vascular structures, such as the blood brain barrier, is considered, consistent with significant roles for LPA signaling in vascular development, function, and disease.

T-bet-dependent S1P5 expression in NK cells promotes egress from lymph nodes and bone marrow

During a screen for ethylnitrosourea-induced mutations in mice affecting blood natural killer (NK) cells, we identified a strain, designated Duane, in which NK cells were reduced in blood and spleen but increased in lymph nodes (LNs) and bone marrow (BM). The accumulation of NK cells in LNs reflected a decreased ability to exit into lymph. This strain carries a point mutation within Tbx21 (T-bet), which generates a defective protein. Duane NK cells have a 30-fold deficiency in sphingosine-1-phosphate receptor 5 (S1P₅) transcript levels, and S1P₅-deficient mice exhibit an egress defect similar to Duane. Chromatin immunoprecipitation confirms binding of T-bet to the S1pr5 locus. S1P-deficient mice exhibit a more severe NK cell egress block, and the FTY720-sensitive S1P₁ also plays a role in NK cell egress from LNs. S1P₅ is not inhibited by CD69, a property that may facilitate trafficking of activated NK cells to effector sites. Finally, the accumulation of NK cells within BM of S1P-deficient mice was associated with reduced numbers in BM sinusoids, suggesting a role for S1P in BM egress. In summary, these findings identify S1P₅ as a T-bet–induced gene that is required for NK cell egress from LNs and BM.

Synaptic PRG-1 modulates excitatory transmission via lipid phosphate-mediated signaling

Plasticity related gene-1 (PRG-1) is a brain-specific membrane protein related to lipid phosphate phosphatases, which acts in the hippocampus specifically at the excitatory synapse terminating on glutamatergic neurons. Deletion of prg-1 in mice leads to epileptic seizures and augmentation of EPSCs, but not IPSCs. In utero electroporation of PRG-1 into deficient animals revealed that PRG-1 modulates excitation at the synaptic junction. Mutation of the extracellular domain of PRG-1 crucial for its interaction with lysophosphatidic acid (LPA) abolished the ability to prevent hyperexcitability. As LPA application in vitro induced hyperexcitability in wild-type but not in LPA(2) receptor-deficient animals, and uptake of phospholipids is reduced in PRG-1-deficient neurons, we assessed PRG-1/LPA(2) receptor-deficient animals, and found that the pathophysiology observed in the PRG-1-deficient mice was fully reverted. Thus, we propose PRG-1 as an important player in the modulatory control of hippocampal excitability dependent on presynaptic LPA(2) receptor signaling.

S1P3-mediated cardiac fibrosis in sphingosine kinase 1 transgenic mice involves reactive oxygen species

AIMS

Sphingosine kinase 1 (SPHK1), its product sphingosine-1-phosphate (S1P), and S1P receptor subtypes have been suggested to play protective roles for cardiomyocytes in animal models of ischaemic preconditioning and cardiac ischaemia/reperfusion injury. To get more insight into roles for SPHK1 in vivo, we have generated SPHK1-transgenic (TG) mice and analysed the cardiac phenotype.

METHODS AND RESULTS

SPHK1-TG mice overexpressed SPHK1 in diverse tissues, with a nearly 20-fold increase in enzymatic activity. The TG mice grew normally with normal blood chemistry, cell counts, heart rate, and blood pressure. Unexpectedly, TG mice with high but not low expression levels of SPHK1 developed progressive myocardial degeneration and fibrosis, with upregulation of embryonic genes, elevated RhoA and Rac1 activity, stimulation of Smad3 phosphorylation, and increased levels of oxidative stress markers. Treatment of juvenile TG mice with pitavastatin, an established inhibitor of the Rho family G proteins, or deletion of S1P3, a major myocardial S1P receptor subtype that couples to Rho GTPases and transactivates Smad signalling, both inhibited cardiac fibrosis with concomitant inhibition of SPHK1-dependent Smad-3 phosphorylation. In addition, the anti-oxidant N-2-mercaptopropyonylglycine, which reduces reactive oxygen species (ROS), also inhibited cardiac fibrosis. In in vivo ischaemia/reperfusion injury, the size of myocardial infarct was 30% decreased in SPHK1-TG mice compared with wild-type mice.

CONCLUSION

These results suggest that chronic activation of SPHK1-S1P signalling results in both pathological cardiac remodelling through ROS mediated by S1P3 and favourable cardioprotective effects.

A reevaluation of tetraploidy in the Alzheimer's disease brain

Alzheimer's disease (AD) is characterized by extensive neuronal death in distinct brain regions, including the frontal cortex and hippocampus, although the specific mechanisms of neuronal degeneration in AD remain a topic of intense scientific pursuit. One model for cell death in AD postulates that abortive cell cycle events in neurons, including tetraploidy, precede neuronal death, and novel therapeutics based on suppressing cell cycle re-entry are being pursued. Using DNA content fluorescence-activated cell sorting combined with fluorescence in situ hybridization and immunostaining, we analyzed neuronal nuclei from postmortem human brain samples from the frontal cortex and hippocampus of nondiseased and AD patients for evidence of tetraploidy. Here, we show that tetraploid nuclei are similarly prevalent in AD and control brains and are exclusively non-neuronal, contrasting with an absence of tetraploid neurons. Our findings demonstrate that neuronal tetraploidy is nonexistent in the AD brain and intimate a reevaluation of neuronal cell cycle re-entry as a therapeutic target for AD.

Identification of neural programmed cell death through the detection of DNA fragmentation in situ and by PCR

Programmed cell death is a fundamental process for the development and somatic maintenance of organisms. This unit describes methods for visualizing both dying cells in situ and for detection of nucleosomal ladders. A description of various current detection strategies is provided, as well as support protocols for preparing positive and negative controls and for preparing genomic DNA.

Behavioral phenotype of maLPA1-null mice: increased anxiety-like behavior and spatial memory deficits

Lysophosphatidic acid (LPA) has emerged as a new regulatory molecule in the brain. Recently, some studies have shown a role for this molecule and its LPA(1) receptor in the regulation of plasticity and neurogenesis in the adult brain. However, no systematic studies have been conducted to investigate whether the LPA(1) receptor is involved in behavior. In this study, we studied the phenotype of maLPA(1)-null mice, which bear a targeted deletion at the lpa(1) locus, in a battery of tests examining neurologic performance, habituation in exploratory behavior in response to low and mild anxiety environments and spatial memory. MaLPA(1)-null mutants showed deficits in both olfaction and somesthesis, but not in retinal or auditory functions. Sensorimotor co-ordination was impaired only in the equilibrium and grasping reflexes. The mice also showed impairments in neuromuscular strength and analgesic response. No additional differences were observed in the rest of the tests used to study sensoriomotor orientation, limb reflexes and co-ordinated limb use. At behavioral level, maLPA(1)-null mice showed an impaired exploration in the open field and increased anxiety-like response when exposed to the elevated plus maze. Furthermore, the mice exhibit impaired spatial memory retention and reduced use of spatial strategies in the Morris water maze. We propose that the LPA(1) receptor may play a major role in both spatial memory and response to anxiety-like conditions.