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Many studies using animals clarify that glial cell line-derived neurotrophic factor (GDNF) has strong neuroprotective and neurorestorative effects on dopaminergic neurons. Several pilot studies clarified the validity of continuous intraputaminal GDNF infusion to patients with Parkinson's disease (PD), although a randomized controlled trial of GDNF therapy published in 2006 resulted in negative outcomes, and controversy remains about the efficacy and safety of the treatment. For a decade, our laboratory has investigated the efficacy and the most appropriate method of GDNF administration using animals, and consequently we have obtained some solid data that correspond to the results of clinical trials. In this review, we present an outline of our studies and other key studies related to GDNF, the current state of the research, problems to be overcome, and predictions regarding the use of GDNF therapy for PD in the future.

CD16+ monocytes, identified as a minor population of monocytes in human peripheral blood, have been implicated in several inflammatory diseases, including rheumatoid arthritis (RA). Fractalkine (FKN, CX3CL1), a member of the CX3 C subfamily, is induced by pro-inflammatory cytokines, while a receptor for FKN, CX3CR1, is capable of mediating both leukocyte migration and firm adhesion. Here, we investigated the role of FKN and CX3CR1 in activation of CD16+ monocytes and their recruitment into synovial tissues in RA patients. High levels of soluble FKN were detected in the synovial fluid and sera of RA patients. Circulating CD16+ monocytes showed a higher level of CX3CR1 expression than CD16- monocytes in both RA patients and healthy subjects. High level expression of CX3CR1 was also seen in CD16+ monocytes localized to the lining layer in RA synovial tissue. In the in vitro culture experiments, IL-10 induced CX3CR1 expression on the surface of monocytes, and TNFalpha induced membrane-bound FKN as well as soluble FKN expression in synovial fibroblasts. Moreover, soluble FKN was capable of inducing IL-1beta and IL-6 by activated monocytes. These results suggest that FKN might preferentially mediate migration and recruitment of CD16+ monocytes, and might contribute to synovial tissue inflammation.

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis induces hyperglycemia and serotonin (5-HT)2A receptor supersensitivity. In the present study, to investigate the effect of hyperglycemia on the function of 5-HT2A receptors, we compared the 5-HT2A receptor-mediated wet-dog shake responses in rats treated with adrenocorticotropic hormone (ACTH), dexamethasone and streptozotocin. ACTH (100 μg/rat per day, s.c.), dexamethasone (1 mg/kg per day, s.c.) and streptozotocin (60 mg/kg, i.p.) produced significant hyperglycemia at 14 days after the start of these treatments, and the hyperglycemia was most pronounced in the streptozotocin-treated rats. The wet-dog shake responses induced by (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2A receptor agonist, were significantly enhanced at 14 days after repeated treatment with ACTH and dexamethasone. However, streptozotocin-induced diabetes had no effect on the wet-dog shake responses. The results of the present study suggest that hyperglycemia is not strongly associated with the enhanced susceptibility of 5-HT2A receptors under the condition of hyperactivity of the HPA axis.

In the present study, we investigated the acute effects of 2 different kinds of stress, namely physical stress (foot shock) and psychological stress (non-foot shock) induced by the communication box method, on the sleep patterns of rats. The sleep patterns were recorded for 6 h immediately after 1 h of stress. Physical and psychological stress had almost opposite effects on the sleep patterns: In the physical stress group, hourly total rapid eye movement (REM) sleep and total non-REM sleep were significantly inhibited, whereas psychological stress enhanced hourly total REM sleep but not total non-REM sleep. Further results showed that total REM sleep, total non-REM sleep, total sleep and the total number of REM sleep episodes in 5 h were reduced, and that sleep latency was prolonged compared to the control group. On the other hand, in the psychological stress group, the total REM sleep in 5 h was increased significantly due to the prolongation of the average duration of REM sleep episodes and reduced REM sleep latency. In addition, the plasma of corticosterone increased significantly after physical stress but not after psychological stress. These results suggested that the sleep patterns, particularly the patterns of REM sleep following physical and psychological stress, are probably regulated by 2 different pathways.

Among the 3 mitogen-activated protein kinases -- ERK, p38 MAPK and JNK -- JNK has been suggested to participate in apoptosis, whereas p38 MAPK is thought to be part of the differentiation response. There are many common inducers of JNK and p38 MAPK, but the mechanisms underlying the differential response to apoptosis and differentiation are poorly understood. We found that heatshock activated p38 MAPK at 3min after exposure to a temperature of 44 in stress-hypersensitive PC12m3 mutant cells, while it activated JNK at 20min after the same heat treatment. However, heat shock activated p38 MAPK 5min after heat treatment and JNK 10min after heat treatment in PC12 parental cells. The extent of phosphorylation of p38 MAPK induced by heat shock in PC12m3 cells was significantly greater than that in PC12 parental cells, and a high level of heat-shock-induced neurite outgrowth was observed only in PC12m3 cells. On the other hand, heat-shock-induced JNK activation appeared more quickly and apoptosis started earlier in PC12 parental cells. These findings indicate that short stress induces p38 MAPK and longer stress induces JNK, and that the response of these kinases to heat shock differs depending on cell type.

We investigated the molecular mechanisms responsible for the induction of apoptosis in mouse monocytic macrophage cell line J774A.1 stimulated by 7-ketocholesterol (7-KC). Cell apoptosis was detected by Annexin V-propidium iodide (PI) staining. The DNA-binding activity of nuclear factor kappa B (NF-kappaB) was assessed by electrophoretic mobility shift assay (EMSA). Results showed that 7-KC-stimulation in J774A.1 cells activated NF-kappaB, which is involved in cell apoptosis, in a time- and dose-dependent manners. 7-KC was also found to increase the binding activity of NF-kappaB to specific DNA binding sites, a possible mechanism for the induction of the cell apoptosis. Moreover, these effects were partially inhibited by pyrrolidine dithiocarbamate (PDTC), an NF-kappaB inhibitor. Taken together, 7-KC may be an important factor in atherosclerosis due to the ability of 7-KC to induce cell apoptosis, which is at least partially mediated through the activation of NF-kappaB.

Ciliary neurotrophic factor (CNTF) has been shown to decrease food intake in mouse models of obesity and to improve insulin sensitivity. It is well known that tight regulation of glucose metabolism is essential for successful gestational outcomes (e.g. fetal growth), and that abnormal insulin resistance is associated with preeclampsia (PE). To investigate the possibility that CNTF might be involved in the regulation of insulin resistance during pregnancy, circulating levels of CNTF were assessed in non-pregnant, normal pregnant, postpartum, and pregnant women with PE. Sera from healthy non-pregnant women (n10), pregnant women (n30:1st trimester;n10, 2nd trimester n10;3rd trimester;n10), postpartum women (n10), and patients with PE (n11) were studied with Western blotting. Circulating CNTF was detected by Western blotting, and the levels of CNTF in pregnant women were decreased as compared with those in non-pregnant women, and tended to decrease as pregnancy progressed. A significant decrease was found in PE as compared with normal pregnancy. Circulating CNTF might be associated with physiological and abnormal insulin resistance during pregnancy.

In considering the characteristics of the action of anxiolytic drugs and their mechanism in the brain, it may be necessary not only to study the behavioral pharmacology but also to perform brain site research. In the present study, the action of anxiolytic drugs was examined with respect to various behaviors that were induced by stimulating the brain areas related to emotions such as reward (pleasure) or aversion in rats. First, the low rate of response in lateral hypothalamic self-stimulation behavior was induced by schedules of low current brain stimulation, variable interval (VI) and differential reinforcement of low rate (DRL). Anxiolytic drugs such as benzodiazepines facilitated these low-rate responses. The drug susceptibility was highest in the low current stimulation, lower in the VI stimulation, and lowest in the DRL stimulation schedules. Furthermore, it was found by the auto-titration method in intracranial self-stimulation behavior that anxiolytic drugs decreased the threshold of stimulation reward. Second, it was recognized using the decremental lever pressing (DLP) paradigm that anxiolytic drugs increased the threshold of aversive stimulation of mesencephalic dorsal central gray (DCG), and this increasing effect of the drug was antagonized by GABA receptor blockers such as biccuculline. Finally, it was examined whether or not the conflict situation is established by combining brain stimulation reward and aversion, such as foot-shock or DCG stimulation. As a result, the conflict behavior was established by combining not only the brain stimulation reward and foot-shock aversion, but also the brain stimulation reward and DCG stimulation aversion. Further anxiolytic drugs exhibited anti-conflict action in both situations. The susceptibility of anxiolytic drugs was higher with respect to the conflict behavior induced by intracranial reward and aversion than to that induced by the conventional method based on milk reward and foot-shock aversion. These results suggest that behavioral methods using brain stimulation can examine the mechanisms of direct drug action at the brain stimulation site. Indeed, in the present brain stimulation behavioral study, anxiolytic drugs such as benzodiazepines increased the stimulation threshold in lateral hypothalamic self-stimulation and inhibited the DCG aversive stimulation, thus resulting in an anticonflict action of the drugs.

Photoelectric dyes absorb light and convert photon energy to electric potentials. To test whether these dyes could be used for retinal prostheses, a simple in vitro screening system was developed. Retinal neurons were cultured from the eyes of chick embryos at the 10-day embryonic stage, at which time no retinal photoreceptor cells have yet developed. Intracellular calcium elevation was observed with Fluo-4 in cultured retinal neurons before and after photoelectric dye was applied at varying concentrations to the culture medium. Five of 7 photoelectric dyes tested in this in vitro system induced intracellular calcium elevation in cultured chick retinal neurons. The intracellular calcium elevation generated by the 5 photoelectric dyes was blocked by extracellular calcium depletion in the case of all 5 dyes, and, except for one dye, by the presence of voltage-gated calcium channel blockers. The photoelectric dyes absorbed light under an inverted microscope and stimulated retinal neurons. This simple in vitro system allows the screening of photoelectric dyes which can be used for retinal prostheses.

We observed the distribution of CD56+ epithelial cells in the pancreatic duct system using 25 fetal, one infantile, 3 normal adult, 4 diabetic, and 8 chronically inflamed pancreatic tissue samples. In the early stage of gestation (12 to 17 weeks), CD56+ cells were commonly seen in the immature tubular structures. They were often continuous to pancreatic islets, and their distribution was similar to that of synaptophysin (Syn)+ cells, suggesting that they are precursors of islet neogenesis. Their number decreased in proportion to gestational age. Instead, from 24 weeks of gestation, luminal cell clusters that were common in interlobular ducts revealed CD56+. These cell clusters were unrelated to islet neogenesis and Syn expression. Similar CD56+ luminal cell clusters were also observed in cases of chronic pancreatitis, whereas they were scarce in normal adult and diabetic tissues. CD56+ cells were also occasionally seen in intralobular ducts, intercalated ducts, and centroacinar cells in cases of chronic pancreatitis. We conclude that there are two types of CD56+ epithelial cells in the pancreatic duct system: CD56+ endocrine cells are numerous during the early stage of gestation, when islet neogenesis appears, while CD56+ luminal cells may represent developmental and regenerative changes of pancreatic ducts.

A new model of status epilepticus (SE), which was induced by intermittent electrical stimulation (20 Hz for 20 sec every min for 180 min) of the deep prepyriform cortex, has been developed in the conscious rat. SE was induced in 9 of 16 rats in the drug-free group. The number of stimulation trains required to induce SE in this status subgroup was 125.6 +/- 12.7 (mean +/- SEM) and the mean duration of self-sustained seizure activity (SSSA) occurring after cessation of the stimulation session was 295.4 +/- 111.4 min. Some animals showed secondary generalized seizures. Significant cell loss was observed in the hippocampal CA3 pyramidal cell layer ipsilateral to the stimulation site and bilateral CA1 areas in the status subgroup compared with the group subjected to sham operation. In addition, there was a significant negative correlation between the duration of SSSA subsequent to the stimulation session and the total number of intact pyramidal neurons observed in the bilateral CA1 and ipsilateral CA3 subfields of the status subgroup. There were significant differences between the status and non-status subgroups with respect to the number of afterdischarges (ADs) and the total AD duration during the stimulation session. Pretreatment with phenobarbital (30 mg/kg) prevented the development of SE and hippocampal cell loss completely. Pretreatment with MK-801, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist (0.25 or 1 mg/kg), also prevented hippocampal cell loss, although it did not block SE generation completely, which suggests dissociation of the mechanisms underlying the development of SE and hippocampal damage. These results indicate that prolonged SSSA actually causes hippocampal damage and it is critically dependent upon NMDA receptor participation.

The changes of rat muscle fiber structure and fiber types after the reunification of the nerve and cross-innervation between the nerve to M. soleus (SOL) and M. extensor digitorum longus (EDL) were cytologically studied and the following results were obtained: 1. After the reunification of the nerve, the tendency toward grouping to a single fiber type was observed, although in normal muscle, the red, white and intermediate fibers were distributed in mosaic pattern. 2. After the cross innervation, the changes of fiber types occurred; namely, in SOL, normally composed of red and intermediate fibers, the three types of fibers appeared after the cross- innervation with the nerve to EDL, which originally was composed of the red, white and intermediate muscle fibers, and vice versa. These changes were observed not only in histochemical sections, but also in the ultrastructural level by electron microscope.

As a link in a series of studies on the effects of blood constituents on the brain function by means of brain perfusion, we used four kinds of artificial blood; namely, the blood containing a low molecular dextran, one containing glutamic acid, one containing essential amino acid group and the one containing both essential amino acid group and glutamic acid. During the perfusion experiments we observed the effects of blood constituents on the function and metabolism of the perfused brain and obtained the following results. 1. When a low molecular dextran is used as the colloid osmotic pressure agent instead of hydrodextran, the amount of the blood flow in the brain is maintained roughly at a certain fixed level throughout the experiment, showing no gradual decreasing tendency. 2. When using the artificial blood supplemented with glutamic acid, EEG of the perfused brain shows an increase in the appearance rate of β32 and β33 bands, approaching closely to the pattern of EEG of unrestrained controls at arousal state. 3. In the case of the blood added with essential amino acids similar to the case using the blood with glutamic acid, EEG approaches towards the alert pattern of the controls. 4. When the perfusion is done with the artificial blood lacking in amino acids, about one hour after the start of the perfusion the amount of glutamic acid and its related compounds in the brain can no longer be maintained at normal level and the decrease, being so marked, brings about a marked decrease also in total amino acid content. 5. When the perfusion blood contains glutamic acid, essential amino acid group or both, the concentrations of amino acids of the brain glutamic acid group and the total amino acid can be maintained approximately at normal level for the duration of over one hour.

The present study showed that many neurons in the adult rat brain possessed a perineuronal sulfated proteoglycan surface coat which reacted to cationic iron colloid and aldehyde fuchsin. This surface coat was stained supravitally with Ehrlich's methylene blue and doubly stained with Ehrlich's methylene blue and aldehyde fuchsin. The surface coat was also stained with Gomori's ammoniacal silver and doubly stained with Gomori's ammoniacal silver and cationic iron colloid. The surface coat was usually expressed together with a nerve cell surface glycoprotein net detectable with lectin Wisteria floribunda agglutinin. These findings indicate that the perineuronal proteoglycan surface coat is identical to Cajal's superficial reticulum and contains some collagenous elements. It was further demonstrated that collagenase digestion erased Gomori's ammoniacal silver impregnation within the perineuronal proteoglycan surface coat.

Antroduodenal contractions were studied in rat preparations. Augmented duodenal contractions occurred spontaneously in coordination with antral contractions in normal and saline-pretreated preparations. The coordination did not occur when muscle layers and the myenteric plexus were transversely cut at the duodenum just anal to the gastroduodenal junction. In silent preparations, the coordinated contractions were produced by neostigmine or domperidone. When the antroduodenal junctional zone was pretreated with benzalkonium chloride, the augmented duodenal contractions did not occur spontaneously, and even after administration of neostigmine and domperidone although antral contractions occurred spontaneously. In these preparations, there were notably few myenteric neurons in the junctional zone, but the neurons were distributed normally in the areas where motility was recorded. The results suggest that myenteric neurons mediate antroduodenal coordinated contractions and that the coordination is modified by myenteric cholinergic excitatory and dopaminergic inhibitory pathways.