A novel antibody targeting sequence 31-35 in amyloid ß protein attenuates Alzheimer's disease-related neuronal damage.

Amyloid ß protein (Aß) plays a critical role in pathogenesis of Alzheimer's disease (AD). Our previous studies indicated that the sequence 31-35 in Aß molecule is an effective active center responsible for Aß neurotoxicity in vivo and in vitro. In the present study, we prepared a novel antibody specifically targeting the sequence 31-35 of amyloid ß protein, and investigated the neuroprotection of the anti-Aß31-35 antibody against Aß1-42 -induced impairments in neuronal viability, spatial memory, and hippocampal synaptic plasticity in rats. The results showed that the anti-Aß31-35 antibody almost equally bound to both Aß31-35 and Aß1-42 , and pretreatment with the antibody dose-dependently prevented Aß1-42 -induced cytotoxicity on cultured primary cortical neurons. In behavioral study, intracerebroventricular (i.c.v.) injection of anti-Aß31-35 antibody efficiently attenuated Aß1-42 -induced impairments in spatial learning and memory of rats. In vivo electrophysiological experiments further indicated that Aß1-42 -induced suppression of hippocampal synaptic plasticity was effectively reversed by the antibody. These results demonstrated that the sequence 31-35 of Aß may be a new therapeutic target, and the anti-Aß31-35 antibody could be a novel immunotheraputic approach for the treatment of AD. © 2016 Wiley Periodicals, Inc.

Humanin protects neurons against apoptosis induced by Abeta31-35 through suppression of intrinsic pathway.

The present study aimed to investigate the effects of humanin (HN) on primary cortical neuronal apoptosis induced by Abeta31-35, and explore the potential mechanisms. Cultured cortical neurons were pretreated with different concentrations of HN (5, 10, 20 micromol/L) for different time period (0, 8 and 16 h) respectively, and then exposed to Abeta31-35 (25 micromol/L) for additional 24 h and the neuronal apoptosis was examined by morphological analysis, flow cytometric assays and TUNEL staining. Caspase activities were measured using a spectrophotometer. Bax expression was measured by Western blot. The results were as follows. (1) Pretreatment with HN (20 micromol/L) for 16 h significantly prevented Abeta31-35-induced apoptosis in cortical neurons; (2) HN significantly decreased Abeta31-35-induced elevation of caspase-3 and -9 activities; (3) HN suppressed Abeta31-35-induced translocation of Bax from the cytosol to mitochondria, but had no effect on overall Bax expression. In conclusions, HN attenuated Abeta31-35-induced cortical neuronal apoptosis by blocking intrinsic caspase-dependent apoptotic pathways.

Abeta(31-35)-induced neuronal apoptosis is mediated by JNK-dependent extrinsic apoptosis pathway.

OBJECTIVE: To investigate whether JNK-caspase-dependent apoptotic pathway is involved in Abeta(31-35)-induced apoptosis of cultured cortical neurons. METHODS: Cultured cortical neurons were treated with Abeta(31-35) (25 micromol/L) for 4 h, 8 h, 16 h and 24 h, respectively. Caspase activities were measured using a spectrophotometer. Levels of c-Jun phosphorylation (p-c-Jun) and Fas ligand (FasL) expression were assessed by immunocytochemistry method and quantified using Image-pro plus11.0 image processing and analysis software. RESULTS: Treatment with Abeta(31-35) (25 micromol/L) for 24 h induced significant increases in the activities of caspase-3 and caspase-8 in the cortical neurons. Besides, Abeta(31-35) could time-dependently enhance the expression of p-c-Jun protein. Moreover, SP600125 application (100 nmol/L) could completely abolish Abeta(31-35) neurotoxicity. The increase in FasL expression was detected at 8 h, 16 h and 24 h after Abeta(31-35) treatment, and SP600125 (100 nmol/L) significantly inhibited FasL expression. CONCLUSION: JNK-c-Jun-FasL-caspase-dependent extrinsic apoptotic pathway plays a critical role in mediating Abeta(31-35)-induced apoptosis of cultured neurons.

[Effects of humanin on elevation of intracellular calcium concentration induced by beta-amyloid peptide(31-35) in cultured cortical neurons.].

The disruption of the intracellular Ca(2+) homeostasis has been reported to be one of the mechanisms of beta-amyloid (Abeta) neurotoxicity in Alzheimeros disease (AD). Abeta(31-35), a small active fragment of Abeta, is believed to possess the similar biological activities of full-length Abeta molecule. Humanin (HN) is a recently identified peptide that suppresses neuronal death initiated by AD-related insults. The present study was to investigate the effects of HN on Abeta(31-35)-induced elevation of [Ca(2+)](i) in cultured cortical neurons by real-time fluorescence imaging technique using the Ca(2+)-sensitive dye, Fura-2/AM. The elevation of [Ca(2+)](i) was observed in cultured neurons exposed to Abeta(31-35) (25 mumol/L) (F340/F380: 1 042.56+/- 83.54, compared with control group: 804.73+/- 48.230, P<0.05, n=10). Pretreatment of HN (10 mumol/L) for 10 min significantly decreased the elevation of [Ca(2+)](i) induced by Abeta(31-35) (25 mumol/L) (F340/F380: 918.788+/- 50.73, compared with Abeta(31-35) group, P<0.05, n=10). When neurons were treated with HN and Abeta(31-35) simultaneously, HN (10 mumol/L) could not change the elevation of [Ca(2+)](i) induced by Abeta(31-35) (F340/F380: 1 036.68+/- 88.96, compared with Abeta(31-35) group, P>0.05, n=10), while HN (20 mumol/L) diminished the elevation of [Ca(2+)](i) induced by Abeta(31-35) (25 mumol/L) significantly (F340/F380: 898.56+/- 76.46, compared with Abeta(31-35) group, P<0.05, n=10). The findings imply that: (1) the disruption of the calcium homeostasis induced by Abeta(31-35) is possibly the basis of the neurotoxicity of Abeta(31-35) in cultured cortical neurons; (2) HN suppresses the elevation of [Ca(2+)](i) induced by Abeta(31-35) in a dose- and time-dependent manner.

Protein kinase C mediates amyloid beta-protein fragment 31-35-induced suppression of hippocampal late-phase long-term potentiation in vivo.

Amyloid beta-protein (Abeta) in the brain of Alzheimer's disease (AD) plays a detrimental role in synaptic plasticity and cognitive function. The effects of Abeta on the early-phase long-term potentiation (E-LTP) have been reported widely. However, whether the late-phase long-term potentiation (L-LTP), which differs from E-LTP mechanistically, is also affected by Abeta is still an open question. The present study examined the effects of intracerebraventricular injection of Abeta fragments 25-35 and 31-35 on the L-LTP in the CA1 area of rat hippocampus in vivo, and further investigated its possible underlying mechanism. Our results showed that: (1) Abeta25-35 (6.25-25 nmol) did not affect the baseline field excitatory postsynaptic potentials, but dose-dependently suppressed multiple high-frequency stimuli-induced L-LTP; (2) Abeta31-35, a shorter Abeta fragment than Abeta25-35, also significantly suppressed L-LTP, with the same suppressive effects as Abeta25-35; (3) pretreatment with PMA (6 nmol/5 microl), a membrane permeable PKC agonist, effectively prevented Abeta31-35-induced deficits in the early and the late components of L-LTP; (4) co-application of Abeta31-35 and chelerythrine (12 nmol/5 microl), a PKC antagonist, caused no additive suppression of L-LTP. These results indicate that both Abeta25-35 and Abeta31-35 can impair hippocampal synaptic plasticity in vivo by suppressing the maintenance of L-LTP, and PKC probably mediates the Abeta-induced suppression of hippocampal L-LTP. In addition, the similar efficacy of Abeta31-35 and Abeta25-35 in L-LTP suppression supports the hypothesis we suggested previously that the sequence 31-35 in Abeta might be the shortest active sequence responsible for the neuronal toxicity induced by full length of Abeta molecules.

[Electrophysiological characteristics of central neuronal dendrites and roles of dendritic back-propagating action potentials in modifications of synaptic plasticity].

For expressing the condolences on the passing away of Dr. Hsiang-Tung Chang, one of the distinguished members of the Chinese Academia of Sciences, the pioneer studies on cortical dendritic potentials that Dr. Chang carried out in the 1950s and the prosperous progresses since then, especially, concerning the modifications of synaptic plasticity by the dendritic back-propagating action potentials were briefly reviewed.

[Cerebellum: how does the modular organization in cerebellum fit with its roles in activities of motor learning and classical conditioning?].

Evidence has been accumulating that the cerebellum in vertebrates contributes not only to the well-known postural balance, motor coordination, and the acquisition of skilled movements, but also to the higher cognitive function. However, there exist controversies about how the modular organization, being uniformly distributed throughout the cerebellum, fits with its roles in the motor learning and the classical conditioning, and these have long been hot spots in neuroscience research. Here, some basic advances in these respects were reviewed.

Electroacupuncture attenuates bone-cancer-induced hyperalgesia and inhibits spinal preprodynorphin expression in a rat model.

Cancer pain impairs the quality of life of cancer patients, but opioid intervention can cause significant side effects that further decrease quality of life. Although electroacupuncture (EA) has been used to treat cancer pain, its mechanisms are largely unknown. To examine its effects and underlying mechanisms on cancer pain, we injected AT-3.1 prostate cancer cells into the tibia to induce bone cancer in the male Copenhagen rat. The resulting pain was treated with 10Hz/2mA/0.4ms pulse EA for 30min daily at the point equivalent to the human acupoint GB30 (Huantiao) between days 14 and 18 after the injection. For sham control, EA needles were inserted into GB30 without stimulation. Thermal hyperalgesia, a decrease in paw withdrawal latency (PWL) to a noxious thermal stimulus, and mechanical hyperalgesia, a decrease in paw withdrawal pressure threshold (PWPT), was measured at baseline and 20min after the EA treatment. Preprodynorphin mRNA and dynorphin were determined by RT-PCR and immunohistochemistry, respectively. Thermal and mechanical hyperalgesia developed ipsilaterally between days 12 and 18 after cancer cell inoculation. EA significantly (P<0.05) attenuated this hyperalgesia, as shown by increased PWL and PWPT, and inhibited up-regulation of preprodynorphin mRNA and dynorphin compared to sham control. Intrathecal injection of antiserum against dynorphin A (1-17) also significantly inhibited the cancer-induced hyperalgesia. These results suggest that EA alleviates bone cancer pain at least in part by suppressing dynorphin expression, and they support the clinical use of EA in the treatment of cancer pain.

Effect of lysophosphatidic acid on differentiation of embryonic neural stem cells into neuroglial cells in rats in vitro.

To study the effect of lysophosphatidic acid (LPA) on the differentiation of embryonic neural stem cells (NSCs) into neuroglial cells in rats in vitro, both oligodendrocytes and astrocytes were detected by their marker proteins galactocerebroside (Gal-C) and glial fibrillary acidic protein (GFAP), respectively, using double-labeling immunocytochemistry. RT-PCR assay was also used for analyzing the expression of LPA receptors in NSCs. Our results showed that: (1) LPA at different concentrations (0.01-3.0 mumol/L) was added to culture medium and cell counting was carried out on the 7th day in all groups. Exposure to LPA led to a dose-dependent increase of oligodendrocytes with the response peaked at 1.0 mumol/L, with an increased percentage of 32.6% (P<0.01) of total cells as compared to that of 8.5% in the vehicle group. (2) LPA showed no effect on the differentiation of NSCs into astrocytes. (3) RT-PCR assay showed that LPA(1) and LPA(3) receptors were strongly expressed while LPA(2) receptor expressed weakly in NSCs. These results suggest that LPA at low concentration might act as an extracellular signal through the receptors in NSCs, mainly LPA(1) and LPA(3) receptors, to promote the differentiation of NSCs into oligodendrocytes, while it exhibits little, if any, conceivable effect on the differentiation of NSCs into astrocytes.

Electroacupuncture attenuates bone cancer pain and inhibits spinal interleukin-1 beta expression in a rat model.

BACKGROUND: Although pain affects the quality of life of cancer patients, current medical treatments are either ineffective or have side effects. In the present study we investigated the effect of electroacupuncture (EA) on cancer-induced hyperalgesia and expression of interleukin-1beta (IL-1beta), upregulation of which is related to the maintenance of persistent pain, in a rat model of bone cancer pain. METHODS: Cancer was induced by injecting AT-3.1 prostate cancer cells into the tibia of male Copenhagen rats. The resulting pain was treated with 10 Hz/2 mA/0.4 ms pulse EA for 30 min daily at the equivalent of the human acupoint GB30 (Huantiao) between Days 14 and 18 after cancer cell inoculation. For sham control, EA needles were inserted into GB30 without stimulation. Thermal hyperalgesia, a decrease in paw withdrawal latency to a noxious thermal stimulus, was measured at baseline and 20 min after EA treatment. IL-1beta and its mRNA were respectively determined by immunohistochemistry and reverse transcription-polymerase chain reaction analysis. RESULTS: Thermal hyperalgesia developed between Days 12 and 18 after cancer cell inoculation. EA significantly (P < 0.05) attenuated this hyperalgesia, increasing paw withdrawal latency from 7.0 +/- 0.3 s to 9.2 +/- 0.4 s, and inhibited the upregulation of IL-1beta and its mRNA compared to the sham control. Intrathecal injection of IL-1 receptor antagonist (IL-1ra, 0.1 mg/rat) also significantly inhibited cancer-induced thermal hyperalgesia. CONCLUSION: The data suggest that EA alleviates bone cancer pain, at least in part by suppressing IL-1beta expression. The results support the clinical use of EA in the treatment of cancer pain.

Promotive action of lysophosphatidic acid on proliferation of rat embryonic neural stem cells and their differentiation to cholinergic neurons in vitro.

Effects of lysophosphatidic acid (LPA), an extracellular phospholipid signal, on the proliferation of rat embryonic neural stem cells (NSCs) and their differentiation into microtubule-associated protein 2 (MAP2)-positive and choline acetyltransferase (ChAT)-positive, i.e. cholinergic-committed neurons, were observed in vitro by [(3)H]-thymidine incorporation, immunocytochemistry, Western blot and other techniques. The results showed that: (1) Lower concentrations of LPA (0.01~1.0 mumol/L) dose-dependently enhanced the uptake of [(3)H]-thymidine by NSCs cultured in specific serum-free medium, indicating a significant promotive action of LPA on the proliferation of NSCs. (2) After fetal bovine serum which induces and commences the differentiation of NSCs, was used in the medium, the lower concentrations of LPA increased the percentages of both MAP2- and ChAT-immunoreactive neurons, with a peak at 0.1 mumol/L LPA in two cases. (3) The promotive effects of LPA on the differentiation of MAP2- and ChAT-positive neurons were also supported by the up-regulation of the expressions of both MAP2 and ChAT proteins detected by Western blot. (4) At the early phase of differentiation of NSCs, the cell migration and neurite extension were enhanced significantly by lower dosages of LPA under phase-contrast microscope. These results suggest that LPA within certain lower range of concentrations promotes the proliferation of NSCs and their differentiation into unspecific MAP2-positive and specific cholinergic-committed neurons, and also strengthens the migration and neurite extension of the newly-generated neuronal (and also glial as reported elsewhere) progenitors.

Is protein kinase C (PKC) involved in nociception?

The study was designed to determine whether the protein kinase C (PKC) is involved in nociceptive c-Fos expression and the concomitant signaling processes of endogenous opioid-like substances (OLS) that modulate c-Fos expression in the spinal dorsal horn following formalin injection into the unilateral hindpaw in rats by using immunocytochemical techniques. In the first part of experiments in which rats were pretreated with intrathecal (i.t.) chelerythrine (Chel), an inhibitor of PKC, the nociceptive c-Fos-like immunoreactive (Fos-LI) neurons in the lumbar dorsal horn ipsilateral to the formalin injection were significantly suppressed with a reduction rate of 60.3% (p < .001) as compared to that in the control group with i.t. saline. In the second part of experiments in which rats were pretreated with i.t. naloxone (Nal), the nociceptive Fos-LI neurons were significantly increased by 53.2% (p < .01) as compared to that in the control group; however, when rats were pretreated with combined i.t. Nal + Chel, the nociceptive Fos-LI neurons exhibited a percentage reduction similar to that in group with i.t. Chel alone, although the real number of Fos-LI neurons in group with i.t. Nal + Chel still significantly surpassed that in group with i.t. Chen only. These results suggest that: (1) PKC may play an important role in the induction of nociceptive c-Fos expression; (2) nociceptive c-Fos expression is subject to the modulation of endogenous OLS that suppress the nociceptive responses of the dorsal horn neurons; and (3) PKC may not be involved in the signaling processes by which the endogenous OLS modulate the nociceptive c-Fos expression in the spinal level.

Amyloid beta-protein fragment 31-35 suppresses long-term potentiation in hippocampal CA1 region of rats in vivo.

Effects of fragment 31-35 of amyloid beta-protein (AbetaP31-35) on the baseline synaptic transmission, shown as fEPSPs, and the long-term potentiation (LTP) induced by high-frequency stimuli (HFS) were investigated in vivo in the hippocampal CA1 region of rats; a longer fragment of AbetaP, i.e., AbetaP25-35, which had been generally accepted as the active center in AbetaP, was also tested comparatively along with AbetaP31-35. The results showed that: (1) the baseline fEPSPs induced by test stimuli were not changed by i.c.v. injection of AbetaP31-35, while application of either AbetaP31-35 or AbetaP25-35 with the same molar concentration (50 nmol) significantly and similarly suppressed the HFS-induced LTP; (2) higher concentration of AbetaP31-35 or longer time of AbetaP exposure exhibited stronger suppression on LTP, indicating a dose- and time-dependent trends; (3) no significant effects could be found on the paired-pulse facilitation (PPF) following AbetaP31-35 injection; (4) pretreatment with verapamil (2.5 mg/kg, i.p., 1 h prior to HFS), a blocker of L-type Ca2+ channels, did not affect the baseline fEPSPs, while it exhibited a significant suppression on LTP induced by HFS; and (5) surprisingly enough, coapplication with verapamil and AbetaP31-35 exhibited a similar suppression on LTP just as both of these two agents were used alone. These results indicate that: (1) AbetaP31-35, similar to AbetaP25-35, possesses potent suppressive effects on hippocampal LTP in vivo, supporting our proposal that the fragment AbetaP31-35 might be to date the shortest active sequence in full-length of AbetaP molecule; (2) AbetaP31-35-induced LTP suppression is not mediated by affecting the presynaptic processes; and (3) L-type Ca2+ channels might be one of the main pathways by which AbetaP31-35 insults LTP.

Apolipoprotein E4 suppresses delayed-rectifier potassium channels in membrane patches excised from hippocampal neurons.

Recent studies show a clear association between Alzheimer's disease (AD) and the apolipoprotein E epsilon 4 allele (APOE4). The mechanisms underlying apoE4-mediated detrimental effects have not been well-clarified. The present study investigates possible effects of apoE4 on the delayed-rectifier potassium (IK) channels in inside-out membrane patches excised from rat hippocampal neurons. Acute application of apoE4 (0.5 microM) to the inside of the membrane patches markedly and reversibly suppressed the single IK channel activities. The average open probability and open frequency of IK channels decreased by (92.6+/-7.1)% and (88.6+/-3.2)%, respectively. The mean open time of IK channels decreased by (81.6+/-6.7)%, and the mean closed-time of them increased by 6.9+/-1.9 fold. Meanwhile, the mean current amplitude of IK channels was not significantly affected. In contrast, application of apolipoprotein A (apoA, 0.5 microM), another member of apolipoprotein family with similar molecular weight and amino acid sequence to apoE4, did not exhibit any effects on IK currents. These results indicate that apoE4 molecules can rapidly suppress the activities of IK channels in hippocampal neurons when they act on the inner side of the neuronal membrane. We propose that the overproduction of apoE4 in neurons may suppress normal IK channel activities and thus be responsible for the late-developed neuronal damages related to the pathogenesis of AD.

[Recent progress in neuroprotection of humanin against Alzheimer's disease-relevant neurotoxicity].

Alzheimer's disease (AD) is the leading cause of dementia for aging people, and far from control due to its obscure mechanism. Humanin, a 24-aa peptide encoded by a newly identified gene cloned from an apparently normal region of AD brain, can specifically attenuate AD-related neurotoxicity. It protects neurons from insults of various AD genes, anti-APP antibodies and Abeta by forming a homodimer outside and interfering directly or indirectly with the activity of Abeta. Humanin seems, however, not to inhibit other toxic insults to neurons, such as Fas or etoposide, an agent against carcinomatous cells in clinical therapy. So Humanin rescues neurons from various AD-related toxicity specifically with efficiency.

Spinal glial activation in a new rat model of bone cancer pain produced by prostate cancer cell inoculation of the tibia.

Studies suggest that astrocytes and microglia in the spinal cord are involved in the development of persistent pain induced by tissue inflammation and nerve injury. However, the role of glial cells in bone cancer pain is not well understood. The present study evaluated the spinal glial activation in a novel rat model of bone cancer pain produced by injecting AT-3.1 prostate cancer cells into the unilateral tibia of male Copenhagen rats. The structural damage to the tibia was monitored by radiological analysis. The thermal hyperalgesia, mechanical hyperalgesia and allodynia, and spontaneous flinch were measured. The results showed that: (1) inoculation of prostate cancer cells, but not the vehicle Hank's solution, induced progressive bone destruction at the proximal epiphysis of the tibia from day 7-20 post inoculation; (2) the inoculation also induced progressive thermal hyperalgesia, mechanical hyperalgesia, mechanical allodynia, and spontaneous flinches; (3) astrocytes and microglia were significantly activated in the spinal cord ipsilateral to the cancer leg, characterized by enhanced immunostaining of both glial fibrillary acidic protein (GFAP, astrocyte marker) and OX-42 (microglial marker); (4) IL-1beta was up-regulated in the ipsilateral spinal cord, evidenced by an increase of IL-1beta immunostained astrocytes. These results demonstrate that injection of AT-3.1 prostate cancer cells into the tibia produces progressive hyperalgesia and allodynia associated with the progression of tibia destruction, indicating the successful establishment of a novel male rat model of bone cancer pain. Further, bone cancer activates spinal glial cells, which may release IL-1beta and other cytokines and contribute to hyperalgesia.

c-Fos antisense oligodeoxynucleotide offsets behavioral nociceptive responses and both up-regulations of c-Fos protein and dynorphin a (1-8) in dorsal horn: a study using the formalin test in rats.

The formalin test was used to elicit acute and chronic pain in rats, and antisense oligodeoxynucleotide (AS-ODN) was used as a tool to modulate the expression of nociceptive behavioral and neurochemical responses. AS-ODN complementary to c-Fos mRNA was administered intrathecally (i.t.) 4 h before formalin injection in the experimental group. Normal saline or reverse AS-ODN was pre-administered i.t. at the same time in two control groups (saline and reverse AS-ODN). The results showed that the acute phase of nociceptive behavior showed no change by AS-ODN administration, whereas the tonic phase of nociceptive licking and biting behavior was significantly suppressed by AS-ODN as compared with the saline or the reverse AS-ODN group, respectively (p < .05 and p < .01). At the same time, both Fos-like immunoreactive (FLI) neurons and density of dynorphin-like immunoreactivities (DLI) were decreased significantly (p < .05 and p < .01) in the AS-ODN group as compared with that in two control groups. The results indicate that the long-lasting nociceptive responses elicited by sustained noxious inputs are based on the up-regulation of c-Fos gene expression, which in turn induces the upregulation of Dyn A production. It is proposed that intensified Dyn A production in the dorsal horn may be pivotal for the appearance of chronic pain.

Mu opioid receptor-containing neurons mediate electroacupuncture-produced anti-hyperalgesia in rats with hind paw inflammation.

Previous studies showed that electroacupuncture (EA) significantly attenuates inflammatory hyperalgesia in a complete Freund's adjuvant (CFA)-induced inflammatory pain rat model. The present study demonstrates that pretreatment with Derm-sap, a selective toxin for neurons that contain mu opioid receptor (MOR), specifically decreases MOR and blocks EA anti-hyperalgesia. These data suggest that spinal MOR-containing neurons are involved in the processes by which EA produces anti-hyperalgesia.

Neuroprotective effect of lysophosphatidic acid on AbetaP31-35-induced apoptosis in cultured cortical neurons.

It has been reported that lysophosphatidic acid (LPA) at its lower concentrations prevents apoptosis induced by serum-deprivation in cultured cortical neurons when LPA is added into the cultural medium with serum withdrawal. The present study was designed to investigate whether LPA could also block the apoptosis induced by beta-amyloid peptide fragment 31-35 (AbetaP31-35) in cultured cortical neurons by using techniques of DNA fragmentation electrophoresis, HO33342 staining, and TUNEL examinations. The results showed that pretreatment of LPA suppressed the AbetaP31-35-induced apoptosis only when LPA was applied to the cultured neurons with lower concentrations (1-10 micromol/L) and especially, with a preceding time of 12-24 h before the AbetaP31-35 exposure. These facts imply that LPA also acts as a neuroprotective factor against AbetaP31-35-induced apoptosis, though the mechanism underlying the protective action in this case may be more complex than that involved in the serum deprivation-induced apoptosis.