[Cannabinoids reduce opioid use in older patients with pain : Retrospective three-year analysis of data from a general practice]. / Cannabinoide reduzieren den Opioidverbrauch bei älteren Schmerzpatienten : Eine retrospektive Dreijahresauswertung einer ambulanten kassenärztlichen Praxis.

BACKGROUND: Relevant data for the prescription and therapeutic effects of medical cannabinoids (CAM) are still missing in everyday medicine especially for elderly and geriatric patients. AIM OF THE STUDY: Documentation of prescription (duration, age) of CAM (dronabinol, nabiximols, cannabinoid extracts) and co-medicated opioids in a doctor's office specializing in pain. METHODS: Analysis of the consumption of opioids (morphine equivalent) and CAM (THC equivalent) for age and gender. RESULTS: In all, 178 patients with chronic pain were treated for a period of 366 days (median; range 31-2590 days). Median age was 72 years (26-96 years); 115 were women (64.8%). Of these, 34 were younger than 65 years, 42 were 65-80 years and 40 were more than 80 years old. Of the 63 men, 29 were younger than 65 years, 24 were 65-80 years and 10 were older than 80 years. Indications for CAM were chronic pain and the limitations for opioids because of side effects and worsening of quality of life. To total of 1001 CAM were prescribed, 557 (55.6%) dronabinol as liquid, 328 (32.7%) as full spectrum extracts and 66 (6.6%) as oro-mucosal nabiximols spray. 50 prescriptions (5%) contained more than one CAM simultaneously. The daily consumption of dronabinol liquor and extracts were 9.6 mg/day (median), and of spray 13.6 mg. The dosage over time did not change in patients older than 64; in younger patients, there was a non-significant increasing trend. Women requested lower THC dosages compared to men (8.1 mg vs. 14.8 mg). Furthermore, 10 patients (5.6%) stopped CAM because of failing effectivity, 7 (3.9%) because of failing cost coverage and only 5 because of adverse side effects. 115 patients (65%) with CAM also received opioids a median 65 mg/day morphine equivalents. This opioid dosage was significantly reduced in course of time by 24 mg/day morphine equivalents or 50%. This reduction was independent on CAM dosage, age and gender. DISCUSSION: Patients with chronic pain profit from long-term CAM which safely and significantly lower the consumption of comedicated opioids, even at low dosages (< 7.5 mg/day). For women, low-dose THC may be sufficient. Older patients benefit from CAM, and adverse effects do not limit the (chronic) use and prescription of CAM in the elderly.

Normal values of quantitative T2' in a spontaneously hypertensive stroke prone rat stem at 3T.

INTRODUCTION: Regarding therapy and prognosis of acute ischemic stroke the identification of ischemic penumbra is pivotal. A promising candidate is BOLD-imaging using qT2'-maps. For valid interpretation of experimental studies in animals normal values for qT2' are needed. Normal values in humans at 1.5T already exist. Normal values for cortical and subcortical structures in a spontaneously hypertensive stroke prone rat stem (SHR-SP) at a fieldstrength of 3T are reported. MATERIALS AND METHODS: 39 (20 males and 19 females) spontaneously hypertensive stroke prone (SHRSP) rats were examined in a 3T scanner using a dedicated small animal coil. Mean weight was 144.1 ± 8.2g and mean age was 60.2 ± 2.7 days. For the calculation of qT2' multiple echo T2w and T2 w images were acquired. ROIs were placed into deep and cortical grey matter in five different brain regions to obtain values for qT2', qT2 and qT2. RESULTS: Mean qT2' for cortical grey matter was 74.76 ± 33.27 ms and 67.73 ± 17.86 ms for deep grey matter. The 99% confidence interval for cortical grey matter was 69.91-79.61 ms. For qT2 it was 79.02 ± 2.9 ms and 70.45 ± 1.89 ms, respectively. For qT2 it was 34.65 ± 5.25 ms and 31.9 ± 2.9 ms. CONCLUSION: The values for qT2' presented here can serve as reference values for further studies examining the ischemic penumbra in a rat model.

The c-Jun N-terminal kinase (JNK) inhibitor XG-102 enhances the neuroprotection of hyperbaric oxygen after cerebral ischaemia in adult rats.

AIM: Both hyperbaric oxygenation (HBO) and inhibition of the c-Jun N-terminal kinases (JNKs) by the peptide inhibitor XG-102 (D-JNKI-1) are efficient protective strategies against ischaemia-induced neurodegeneration. The present study investigated whether the combination of HBO and JNK inhibitor, XG-102, provides additive neuroprotection against cerebral ischaemia. METHODS: Rat middle cerebral artery was occluded (MCAO) for 90 min. XG-102 [2 mg/kg, intraperitoneally] or HBO (3 ATA, 60 min) was applied 3 h after the onset of MCAO. For the combination treatment, HBO was started 10 min after the injection of XG-102. Twenty-four hours after MCAO, the infarct area, the neurological score and the immunohistochemistry staining in brain slices for cleaved-PARP, transferase-mediated biotinylated UTP nick end labelling, c-Jun and phosphorylated (activated) c-Jun were observed. RESULTS: XG-102 or HBO alone reduced the total infarct area by 43% and 63%, respectively. The combination diminished total infarct area by 78%, improved the neurological function and reduced brain oedema. Co-application of HBO and XG-102 also significantly reduced the cleavage of PARP, by 96% and 91% in cortical penumbra and ischaemic core, respectively. Moreover, cotreatment significantly attenuated the number of cells labelled with transferase-mediated biotinylated UTP nick end labelling and phosphorylated c-Jun. CONCLUSION: Our study demonstrates that HBO reinforces the efficiency of neuroprotective drugs such as XG-102 and vice versa. Both treatments, physical HBO and pharmacological XG-102, are already in phase I/II studies and promising strategies for clinical use.

Specific activities of individual c-Jun N-terminal kinases in the brain.

The c-Jun N-terminal kinases (JNKs) are multifunctional molecules which, on the one hand, regulate various processes in brain development, repair and memory formation. On the other hand, JNKs are potent effectors of neuronal death and neuroinflammation. This review summarizes recent findings on individual JNK functions in the nervous system under pathophysiological conditions and on their regulation by upstream kinases, phosphatases and formation of context-dependent signalosomes. By focusing on different aspects of JNK signaling, it becomes increasingly obvious that the JNK cascade is intricately regulated and intensely dependent on the availability and functionality of its single components and their intracellular localization. Our review also emphasizes, that JNKs are indispensable for neuronal cell death as well as many physiological functions in the brain. Finally, we discuss pharmacological strategies which target pathological JNK activities without affecting their physiological functions.

Neuroprotection by oxygen in acute transient focal cerebral ischemia is dose dependent and shows superiority of hyperbaric oxygenation.

The neuroprotective effect of oxygen after acute stroke in rats has been shown previously. However, the question of optimal dosing still remains unanswered. Thus, we investigated the use of oxygen at different concentrations by either normobaric oxygenation (NBO) or hyperbaric oxygenation (HBO) at different pressures in a model of transient ischemia/reperfusion in rats. Animals underwent 90 min of middle cerebral artery occlusion (MCAO) followed by 90 min of reperfusion before oxygen treatment. Oxygen was applied either by NBO (100% O(2); 1.0 absolute atmosphere, ATA) or HBO (100% O(2); 1.5, 2.0, 2.5 or 3.0 ATA) for 1 h. Primary endpoints were infarct volume and clinical outcome measured 24 h and 7 days following the MCAO. A statistically significant and long-lasting reduction in infarct volume was seen in the HBO 2.5 ATA and 3.0 ATA groups over a period of 7 days. The reduced infarct volume was accompanied with a statistically significant improvement in clinical outcome in the high-dose oxygen-treated groups. The presented data indicate that oxygen is a highly neuroprotective molecule in transient focal cerebral ischemia in rats, when applied early and at high doses. The effect is dose dependent and shows a superiority of HBO over NBO, when the primary endpoints infarct volume reduction and clinical outcome are analyzed. These data are important for the development of new acute stroke treatment studies in humans.

c-Jun N-terminal kinases trigger both degeneration and neurite outgrowth in primary hippocampal and cortical neurons.

We provide a comprehensive analysis on c-Jun N-terminal kinase (JNK) actions leading to death or differentiation in postnatal hippocampal and cortical neurons. Stimulation with glutamate or 6-hydroxy-dopamine caused activation of caspase-3 and apoptotic neuronal death which were both attenuated by JNK-inhibition. In cortical neurons, stress-induced nuclear JNK distribution was rather complex. We observed a decrease of activated and total JNK in the nucleus after stimulation, but an increase of the phosphorylated transcription factor c-Jun. Isoform-analysis revealed a nuclear translocation of JNK2, while nuclear protein levels of JNK1 decreased. This activation pattern differed from neurite formation. In hippocampal and cortical neurons, JNK activity continuously increased during neuritogenesis, whereas levels of phosphorylated c-Jun gradually declined. Despite these similarities, JNK inhibition by SP600125 only affected neurite outgrowth in hippocampal cells. Furthermore, experiments in JNK-deficient mice demonstrated that all JNK isoforms contributed to neuritogenesis. Summarizing, JNKs are involved in both neuritogenesis and death of primary neurons with differentially regulated nuclear translocation of specific isoforms after degenerative stress, while neuritogenesis is supported by all JNK isoforms.

Luteolin protects rat PC12 and C6 cells against MPP+ induced toxicity via an ERK dependent Keap1-Nrf2-ARE pathway.

Oxidative stress is central to neuronal damage in neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. In consequence, activation of the cerebral oxidative stress defence is considered as a promising strategy of therapeutic intervention. Here we demonstrate that the flavone luteolin confers neuroprotection against oxidative stress via activation of the nuclear factor erythroid-2-related factor 2 (Nrf2), a transcription factor central to the maintenance of the cellular redox homeostasis. Luteolin protects rat neural PC12 and glial C6 cells from N-methyl-4-phenyl-pyridinium (MPP+) induced toxicity in vitro and effectively activates Nrf2 as shown by ARE-reporter gene assays. This protection critically depends on the activation of Nrf2 since downregulation of Nrf2 by shRNA completely abrogates the protection of luteolin in vitro. Furthermore, the neuroprotective effect of luteolin is abolished by the inhibition of the luteolin-induced ERK1/2-activation. Our results highlight the relevance of Nrf2 for neural cell survival conferred by flavones. In particular, we identified luteolin as a promising lead for the search of orally available, blood brain barrier permeable compounds to support the therapy of neurodegenerative disorders.

Serum anticholinergic activity in patients following cardiac surgery and healthy individuals following amitriptyline application.

The serum anticholinergic activity (SAA) is used as a marker for cognitive impairment. Here, two studies have been performed characterizing the SAA profile. In Study 1 the endogenous SAA in relation to the total serum protein concentration was monitored for 24 h in five healthy individuals and compared with that in four inpatients following cardiac surgery. In Study 2 the SAA of seven healthy individuals was assessed following a single amitriptyline dose. In both studies SAA was assessed by an ex vivo assay. In Study 1, the absolute SAA varied in a wide range of 1.2 and 14.5 atropine equivalents (AEs) over 24 h. A circadian pattern was not observed. The mean total serum protein concentration, but not the SAA, was significantly lower in inpatients than in healthy individuals. In Study 2, the SAA increased following amitriptyline to a maximum. The mean SAA increased by 6.39 AE at the amitriptyline peak concentration. High SAA variability showed a low statistical relation to amitriptyline concentrations. Both studies characterize the SAA as an individual parameter not affected per se by surgery or clinical care and poorly correlated with the total serum protein concentration. The relation with amitriptyline concentration helps to quantify SAA values towards a better understanding of the clinical implications and limitations of SAA changes.

Genetic deletion of JNK1 and JNK2 aggravates the DSS-induced colitis in mice.

The c-Jun N-terminal kinases (JNKs) are considered as novel targets for therapy of inflammatory bowel diseases (IBD). However, the relevant JNK isoforms have to be elucidated. Here, we analyze the individual contribution of the JNK1 and JNK2 isoforms in a dextran sulfate sodium (DSS) model of experimental colitis. JNK1 and JNK2 knockout mice (JNK1 ko, JNK2 ko) and their wild-type controls (WT1, WT2) received three cycles of DSS treatment, each consisting of 1.7% DSS for 5 days, followed by 5 days with water. Animals were daily evaluated by a disease activity index (DAI) comprising measurement of body weight, estimation of stool consistency, and test for occult blood/gross rectal bleeding. After 30 days all animals were sacrificed, and the inflamed intestine was histologically evaluated by a crypt damage score. Unexpectedly, neither JNK1 ko nor JNK2 ko prevented mice from developing a chronic colitis when compared to wild-type controls WT1 and WT2, respectively. On the contrary, DAI and mortality were aggravated in JNK2 ko compared to WT2. DAI and mortality did not differ between JNK1 ko and WT1, but the histological crypt damage score was significantly enhanced in the cecum of JNK1 ko mice. Genetic deletion of JNK2 worsens the disease outcome in an experimental model of murine colitis. We hypothesize that the functional deletion of the otherwise proapoptotic JNK2 prolongs the activity of proinflammatory immune cells with deterioration of disease activity.

Induction of immediate early gene expression by high-frequency stimulation of the subthalamic nucleus in rats.

Deep brain stimulation is associated with delayed improvement of parkinsonian symptoms, such as hypokinesia with subthalamic nucleus stimulation, or dystonia with globus pallidus internus stimulation. The latency observed is better explained by molecular alterations than immediate electrophysiological processes, and clinical improvement may involve adaptive gene expression. Here, we have studied immediate early gene expression as fast molecular response to subthalamic nucleus stimulation. Bipolar electrodes were implanted bilaterally into the subthalamic nucleus of anesthetized male Wistar rats. High-frequency stimulation (130 Hz or 80 Hz, 60 micros, 300 microA) or low-frequency stimulation (5 Hz, 60 micros, 300 microA) was performed with the right electrode for 15, 60, 120, and 240 min whereas the silent left electrode served as negative control. Brains were fixed by transcardial perfusion and frozen sections were stained with polyclonal antibodies directed against three immediate early gene-encoded proteins, c-Fos, c-Jun, and Krox-24 (NGFI-A, Egr-1, Zif268, Tis8, Zenk). After 120 and 240 h, c-Fos immunoreactivity was strongly upregulated in subthalamic nucleus neurons on the stimulated site. In contrast, no c-Fos immunoreactivity was detected on the non-stimulated site except for single positive cells located in close proximity to the electrode tracks. Furthermore, c-Fos immunoreactivity was induced in subthalamic nucleus projection areas, such as primary and secondary motor cortex, primary somatosensory and insular cortex, lateral and medial globus pallidus, suprageniculate thalamic nucleus, pontine nuclei, medial geniculate nucleus, and substantia nigra. Similarly, c-Jun and Krox-24 were induced at the site of stimulation and in projection areas following high-frequency subthalamic nucleus stimulation. Whereas high frequency stimulation with 80 Hz was similarly effective none of the three immediate early gene-encoded proteins was induced with low-frequency stimulation (5 Hz) for 4 h. This is in accordance with the therapeutic effects of deep brain stimulation which are only elicited with high frequency stimulation. Our data provide evidence that immediate early gene expression in the subthalamic nucleus is rapidly and substantially induced by high-frequency stimulation. The induction of immediate early genes in projection sites suggests ipsilateral transsynaptic modulation of neuronal activity.

Depletion of the AP-1 repressor JDP2 induces cell death similar to apoptosis.

JDP2 is a ubiquitously expressed nuclear protein that efficiently represses the activity of the transcription factor AP-1. Thus far, all studies of JDP2 function have relied on the ectopic expression of the protein. In this study, we use a different approach: depletion of JDP2 from cells. Specific depletion of JDP2 resulted in p53-independent cell death that resembles apoptosis and was evident at 72 h. The death mechanism was caspase dependent as the cells could be rescued by treatment with caspase inhibitor zVAD. Our studies suggest that JDP2 functions as a general survival protein, not only following UV-irradiation, as reported earlier, but also under normal culture conditions. Thus, our data support that JDP2 is a cellular survival protein whose presence is necessary for normal cellular function.

JNK2 mediates TNF-induced cell death in mouse embryonic fibroblasts via regulation of both caspase and cathepsin protease pathways.

Recent studies strongly suggest an active involvement of the c-Jun N-terminal kinase (JNK) signaling pathway in tumor necrosis factor (TNF)-induced apoptosis. The direct evidence for the role of JNK and its isoforms has been missing and the mechanism of how JNK actually could facilitate this process has remained unclear. In this study, we show that Jnk2-/- primary mouse embryonic fibroblasts (pMEFs) exhibit resistance towards TNF-induced apoptosis as compared to corresponding wild-type and Jnk1-/- pMEFs. JNK2-deficient pMEFs could be resensitized to TNF via retroviral transduction of any of the four different JNK2 splicing variants. Jnk2-/- pMEFs displayed deficient and delayed effector caspase activation as well as impaired cytosolic cystein cathepsin activity: processes that both were needed for efficient TNF-induced apoptosis in pMEFs. Our work demonstrates that JNK has a central role in the promotion of TNF-induced apoptosis in pMEFs, and that the JNK2 isoform can regulate both mitochondrial and lysosomal death pathways in these cells.

Changes in peptidyl-prolyl cis/trans isomerase activity and FK506 binding protein expression following neuroprotection by FK506 in the ischemic rat brain.

FK506 is an immunosuppressant also showing neuroprotection following cerebral ischemia. FK506 binds to intracellular proteins (FKBP) which have a wide range of functions but have in common the peptidyl-prolyl cis/trans isomerase activity. Following transient focal ischemia, we have analyzed the expression of FKBP12, 52 and 65 and the total FKBP enzyme activity. Furthermore, we have investigated the effect of FK506 on signal transduction in neurons and perfusion changes in the infarct area. After 90 min of transient middle cerebral artery occlusion in male rats the expression of FKBP12, 52 and 65 was analyzed by Western blot in FK506-treated and control animals and the peptidyl-prolyl cis/trans isomerase activity was determined. Magnetic resonance imaging was used to measure tissue perfusion, development of vasogenic edema and infarct size. To investigate the neuronal stress signal cascade, activating transcription factor 2 (ATF-2), Fas-ligand (Fas-L) and c-Jun expression and phosphorylation were analyzed by immunohistochemistry. FK506 decreased the cerebral infarct volume by 53% and reduced the cytotoxic edema. The total FKBP enzymatic activity in the infarct area was increased and blocked dose dependently by FK506. FKBP expression was selectively up-regulated by cerebral ischemia. FK506 treatment does not influence the expression patterns. c-Jun phosphorylation in neurons of the peri-infarct area and Fas-L expression was reduced by FK506 treatment whereas ATF-2 expression was preserved. Cerebral ischemic damage to the brain was reduced by FK506. It was shown for the first time that neuroprotection by FK506 also included the suppression of the cerebral peptidyl-prolyl cis/trans isomerase activity of FKBP in vivo whereas the expression levels of FKBP12, 52 and 65 following ischemia changed slightly and FK506 treatment does not suppress the expression patterns. However, changes of FKBP enzymatic activity result in suppression of the stress cell body response in the peri-infarct area as observed by suppression of c-Jun phosphorylation and Fas-L expression.

Memory retrieval after contextual fear conditioning induces c-Fos and JunB expression in CA1 hippocampus.

Using specific polyclonal antisera against c-Fos, JunB, c-Jun and JunD, we tried to identify the candidate transcription factors of the immediate early gene family which may contribute to the molecular processes during contextual memory reconsolidation. For that purpose we analyzed the expression of these proteins in the hippocampus after contextual memory retrieval in a mouse model of fear conditioning. A single exposure to a foot shock of 0.8 mA was sufficient to induce robust contextual fear conditioning in C57BI/6N mice. In these mice context dependent memory retrieval evoked a marked induction of c-Fos and JunB, but not of c-Jun and JunD, in pyramidal CA1 neurons of the dorsal hippocampus. In contrast, mice exposed and re-exposed only to the context, without foot shock, did not show behavioral signs of contextual fear conditioning and exhibited significantly less expression of c-Fos and JunB in CA1 neurons. Mice which received a foot shock but were not re-exposed to the context revealed no immediate early gene induction. These results demonstrate that contextual memory retrieval is associated with de novo synthesis of specific members of the Fos/Jun transcription factor family. Therefore we suggest that these genes may contribute to plasticity and reconsolidation accompanying the retrieval process. The specific activation of CA1 neurons during the retrieval of contextual fear associations supports the postulated concept of a mnemonic role of this hippocampal subsector during the retrieval of contextual informations.

The neuroprotective actions of FK506 binding protein ligands: neuronal survival is triggered by de novo RNA synthesis, but is independent of inhibition of JNK and calcineurin.

The immunosuppressant FK506 displays substantial neuroprotective and neuroregenerative effects. It is not fully understood to which extent these effects depend on the inhibition of the calcineurin phosphatase (PP2B). The present study has re-addressed this issue using Lie120, a novel highly specific inhibitor of calcineurin, which does not block the enzymatic activity of FKBPs or cyclophilins, respectively. We have determined the effect of FK506 (10-500 nM), V-10,367 (a FK506 derivative which does not block calcineurin; 1-5 microM) and Lie120 (a novel specific inhibitor of calcineurin, 0.1-5 microM) on the cellular survival and the pro-degenerative JNK activity of PC12 and Neuro2A cells following application of 200 microM H(2)O(2). FK506 and V-10,367, but not Lie120, protected both cell lines against H(2)O(2)-mediated death, whereas an increase in JNK1 activity was blocked by FK506 and Lie120, but not by V-10,367. Co-incubation of FK506 and V-10,367 with the mRNA synthesis inhibitor actinomycin D abolished the protective effect of FK506 and V-10,367. This antagonization was effective when actinomycin D was applied 30 min or 1 h, but not 2 or 4 h, after H(2)O(2) suggesting that FKBP-ligands confer their neuroprotection by rapid de novo synthesis of (functionally) anti-apoptotic proteins. The search for the corresponding effector genes revealed that the expression of FKBP25, FKBP38 and FKBP52 (analysis by reverse transcription-polymerase chain reaction (RT-PCR) did not change following H(2)O(2) or FK506, and this was also true for the expression of apoptosis-related genes caspase 3, bax, bcl-2 and bcl-xL (analysis by Multiplex-PCR). Summarizing, neuronal protection by FKBP-ligands is not mediated either by calcineurin or by JNK1 in this experimental set-up, whereas the FK506 mediated inhibition of JNK1 is realized by the inhibition of calcineurin, an effective activator of JNK1 in neurons.

Caspase-3 activation and DNA fragmentation in primary hippocampal neurons following glutamate excitotoxicity.

Excitotoxic glutamate CNS stimulation can result in neuronal cell death. Contributing mechanisms and markers of cell death are the activation of caspase-3 and DNA fragmentation. It remains to be resolved to which extent both cellular reactions overlap and/or indicate different processes of neurodegeneration. In this study, mixed neuronal cultures from newborn mice pubs (0-24 h) were stimulated with glutamate, and the co-localization of active caspase-3 and DNA fragmentation was investigated by immunocytochemistry and the TUNEL nick-end labelling. In untreated cultures, 8% scattered neurons (marked by MAP-2) displayed activated caspase-3 at different morphological stages of degeneration. TUNEL staining was detected in 5% of cell nuclei including GFAP-positive astrocytes. However, co-localization of active caspase-3 with TUNEL was less than 2%. After glutamate stimulation (125 microM), the majority of neurons was dying between 12 and 24 h. The absolute number of active caspase-3 neurons increased only moderately but in relation of surviving neurons after 24 h from 8 to 36% (125 microM), to 53% (250 microM) or to 32% (500 microM). TUNEL staining also increased after 24 h following glutamate treatment to 37% but the co-localization with active caspase-3 remained at the basal low level of 2%. In our system, glutamate-mediated excitotoxicity effects the DNA fragmentation and caspase-3 activation. Co-localization of both parameters, however, is very poor. Active caspase-3 in the absence of TUNEL indicates a dynamic degenerative process, whereas TUNEL marks the end stage of severe irreversible cell damage regardless to the origin of the cell.

AP-1 proteins in the adult brain: facts and fiction about effectors of neuroprotection and neurodegeneration.

Jun and Fos proteins are induced and activated following most physiological and pathophysiological stimuli in the brain. Only few data allow conclusions about distinct functions of AP-1 proteins in neurodegeneration and neuroregeneration, and these functions mainly refer to c-Jun and its activation by JNKs. Apoptotic functions of activated c-Jun affect hippocampal, nigral and primary cultured neurons following excitotoxic stimulation and destruction of the neuron-target-axis including withdrawal of trophic molecules. The inhibition of JNKs might exert neuroprotection by subsequent omission of c-Jun activation. Besides endogenous neuronal functions, the c-Jun/AP-1 proteins can damage the nervous system by upregulation of harmful programs in non-neuronal cells (e.g. microglia) with release of neurodegenerative molecules. In contrast, the differentiation with neurite extension and maturation of neural cells in vitro indicate physiological and potentially neuroprotective functions of c-Jun and JNKs including sensoring for alterations in the cytoskeleton. This review summarizes the multiple molecular interfunctions which are involved in the shift from the physiological role to degenerative effects of the Jun/JNK-axis such as cell type-specific expression and intracellular localization of scaffold proteins and upstream activators, antagonistic phosphatases, interaction with other kinase systems, or the activation of transcription factors competing for binding to JNK proteins and AP-1 DNA elements.

Effect of repetitive icv injections of ANG II on c-Fos and AT(1)-receptor expression in the rat brain.

ANG II has been implicated in neuroplastic processes via stimulation of inducible transcription factors (ITF) in the brain. In the present study, we investigated the effects of acute vs. repetitive once daily intracerebroventricular injections of ANG II for 7 days on the expression of ITF and constitutive transcription factor (CTF) and the AT1 receptor in the median preoptic area (MnPO), the subfornical organ (SFO), and the hypothalamic paraventricular (PVN) and supraoptic nuclei (SON). After repetitive injections, the expression of c-Fos declined by approximately 50% in MnPO, SFO, PVN, and SON compared with controls injected once. The desensitization of c-Fos occurred on the transcriptional level as shown in the SON by RT-PCR. Apart from a novel expression of c-Jun in the SON, the ITF c-Jun, JunB, JunD, and Krox-24 did not change after repetitive stimulation. Neither were the CTF, calcium response element binding protein, activating transcription factor 2, and serum response factor altered after repetitive vs. single injections of ANG II. The AT1 receptor was coexpressed with c-Fos/c-Jun. Immunohistochemical stainings suggest an increase in AT1-receptor number in MnPO, SFO, PVN, and SON on chronic stimulation compared with once-injected controls. These findings demonstrate that repetitive periventricular stimulation with ANG II essentially alters the expression of transcription factors compared with acute stimulation and suggest c-Fos and c-Jun as major intermediates of the AT1-receptor transcription.

The JNK and p38 signal transduction following axotomy.

The transection of nerve fibers evokes a characteristic reaction in the injured neurons, the so-called cell body response (CBR), which comprises aspects of developmental re-differentiation with parallel loss of the transmittory phenotype, efforts or achievement of axonal elongation and re-construction of effective synapses. Neither the signals underlying the onset of CBR nor the programs underlying regeneration are sufficiently elucidated. Here we review the putative role of two subfamilies of the MAP kinases, the JNKs (c-Jun N-terminal kinases) and the p38 kinases in the CBR. Following nerve injury with subsequent CBR, JNKs are rapidly activated and this activation persists for weeks until neu-ronal cell death or successful regeneration. The various functions render JNKs to perfect candidate molecules for the realization of the CBR including axonal transport, activation of c-Jun, modulation of cytoskeletal functions, detection of cytoskeletal alterations, or signal transduction of adhesion molecules in the axon and growth cone. On the other hand, the rapid but transient activation of p38 might interfere with the mitotic arrest, a putative feature of the CBR.

FKBP ligands as novel therapeutics for neurological disorders.

Given their clinical importance for the treatment of acute and chronic neurodegenerative diseases in humans including nerve injuries (e.g. Alzheimer's disease, Parkinson's disease, diabetic neuropathy) a number of different approaches were pursued to obtain selectively acting FK506-binding protein (FKBP) ligands: computational methods and target-oriented screening of natural compound and synthetic product libraries. The resulting monofunctional ligands, which inhibit the peptidyl prolyl cis/trans isomerase activity of FKBPs, highlight the role of these enzymes in neuronal signaling. The exploration of the mechanisms of neuroregenerative and neuroprotective action of some of these compounds is the main focus of ongoing neuropharmaceutical research.