Distinct effects of CGRP on typical and atypical smooth muscle cells involved in generating spontaneous contractions in the mouse renal pelvis

Background and purpose:

We investigated the cellular mechanisms underlying spontaneous contractions in the mouse renal pelvis, regulated by calcitonin gene-related peptide (CGRP).

Experimental approach:

Spontaneous contractions, action potentials and Ca²⁺ transients in typical and atypical smooth muscle cells (TSMCs and ATSMCs) within the renal pelvis wall were recorded separately using tension and intracellular microelectrode recording techniques and Fluo-4 Ca²⁺ imaging. Immunohistochemical and electron microscopic studies were also carried out.

Key results:

Bundles of CGRP containing transient receptor potential cation channel, subfamily V, member 1-positive sensory nerves were situated near both TSMCs and ATSMCs. Nerve stimulation reduced the frequency but augmented the amplitude and duration of spontaneous phasic contractions, action potentials and Ca²⁺ transients in TSMCs. CGRP and agents increasing internal cyclic adenosine monophosphate (cAMP) mimicked the nerve-mediated modulation of TSMC activity and suppressed ATSMCs Ca²⁺ transients. Membrane hyperpolarization induced by CGRP or cAMP stimulators was blocked by glibenclamide, while their negative chronotropic effects were less affected. Glibenclamide enhanced TSMC Ca²⁺ transients but inhibited ATSMC Ca²⁺ transients, while both 5-hydroxydecanoate and diazoxide, a blocker and opener of mitochondrial ATP-sensitive K⁺ channels, respectively, reduced the Ca²⁺ transient frequency in both TSMCs and ATSMCs. Inhibition of mitochondrial function blocked ATSMCs Ca²⁺ transients and inhibited spontaneous excitation of TSMCs.

Conclusions and implications:

The negative chronotropic effects of CGRP result primarily from suppression of ATSMC Ca²⁺ transients rather than opening of plasmalemmal ATP-sensitive K⁺ channels in TSMCs. The positive inotropic effects of CGRP may derive from activation of TSMC L-type Ca²⁺ channels. Mitochondrial Ca²⁺ handling in ATSMCs also plays a critical role in generating Ca²⁺ transients.     

Neuropathological investigation of the hypometabolic regions on positron emission tomography with [18F] fluorodeoxyglucose in patients with dementia with Lewy bodies

We performed a quantitative neuropathological examination of the hypometabolic regions on FDG PET in dementia with Lewy bodies (DLB), Alzheimer's disease (AD) and control cases. When the DLB cases were divided into two groups according to concomitant AD pathology (ADP), neuronal loss in the temporo-parietal association area was milder in the DLB groups than in the AD group, although there were no differences between the two DLB groups. Tau and Aβ immunoreactivities were observed in the AD group and the DLB group with ADP, but were rare in the DLB group without ADP. Tau and Aβ immunoreactivities as well as numbers of neurofibrillary tangles (NFTs) and neuritic plaques (NPs) were more common in the AD group than in the DLB group with ADP. There was no difference in neuronal loss in the occipital area among the three groups. α-Synuclein immunoreactivity was observed in the DLB groups but not in the AD group. There were no differences in α-synuclein immunoreactivity and number of Lewy bodies (LBs) between the two DLB groups. These findings indicate that the neuropathological bases of the hypometabolic regions in the temporo-parietal association and occipital area in DLB may be AD pathology and Lewy pathology, respectively.     

Comparative effects of angiotensin II on the contractility of muscularis mucosae and detrusor in the pig urinary bladder

To explore contractile actions of angiotensin II (ATII) on the muscularis mucosae (MM) of the bladder, ATII‐induced contractions were compared between MM and the detrusor smooth muscle (DSM) of the pig bladder by isometric tension recordings. Effects of ATII on spontaneous Ca²⁺ transients in MM were visualized using Cal‐520 fluorescence. ATII receptor type 1 (ATR1) expression in MM and DSM was also examined by immunohistochemistry. ATII (1 nM–1 μM) caused phasic contractions of MM in a concentration‐dependent manner, while ATII (10 nM–10 μM) had no or marginal effects on DSM contractility. ATII (100 nM)‐induced MM contractions had an amplitude of approximately 70% of carbachol (1 μM)‐induced or 90% of U46619 (100 nM)‐induced contractions. Candesartan (10 nM), an ATR1 blocker, prevented the contractile effects of ATII (1 nM) in MM, while ATR1 immunofluorescence was greater in MM than DSM. ATII (10–100 pM) increased the frequency but not the amplitude of spontaneous Ca²⁺ transients in MM. Both urothelium‐intact and ‐denuded MM strips developed comparable spontaneous phasic contractions, but ATII, carbachol and U46619‐induced contractions were significantly larger in urothelium‐denuded than urothelium‐intact MM strips. In conclusion, the MM appears to have a much greater sensitivity to ATII compared with DSM that could well sense circulating ATII, suggesting that MM may be the predominant target of contractile actions induced by ATII in the bladder while the urothelium appears to inhibit MM contractility.     

Neuropathologic features of frontotemporal lobar degeneration with ubiquitin-positive inclusions with progranulin gene (PGRN) mutations

Frontotemporal lobar degeneration is heterogeneous; cases with tau- and synuclein-negative, ubiquitin-positive neuronal inclusions are the most common, and some have mutations in the gene for progranulin (PGRN). The purpose of this study was to determine whether there were distinctive clinical and neuropathologic features of frontotemporal lobar degeneration with ubiquitin-positive inclusions with PGRN mutations. A retrospective review of medical records and semiquantitative neuropathologic analysis was performed on 18 PGRN(+) and 24 PGRN(-) cases. Clinically, PGRN(+) cases had more frequent language impairment and parkinsonism. Pathologically, PGRN(+) cases had smaller brains, more marked global atrophy, and more frontal atrophy. There was no difference in the frequency of hippocampal sclerosis. The pathology of PGRN(+) cases was relatively homogeneous, whereas PGRN(-) cases were more heterogenous. PGRN(+) cases had greater density of cortical ubiquitin-immunoreactive lesions, especially dystrophic neurites in layer II. Intranuclear inclusions were present in all PGRN(+) and 42% of PGRN(-) cases. The results suggest that frontotemporal lobar degeneration with ubiquitin-positive inclusions due to PGRN mutations has several characteristic features, including ubiquitin-immunoreactive neuritic pathology in superficial cortical layers and neuronal intranuclear inclusions. On the other hand, there is no histopathologic feature or combination of features that is pathognomonic. Neuronal intranuclear inclusions are virtually always present, but they can be detected in PGRN(-) cases.     

Immunohistochemical investigation of neurofibrillary tangles and their tau isoforms in brains of limbic neurofibrillary tangle dementia

Limbic neurofibrillary tangle dementia (LNTD) is a subset of senile dementia characterized by numerous neurofibrillary tangles (NFT) in the hippocampal area, although there is an absence or scarcity of amyloid deposits (AM) throughout the brain. In the present study, we immunohistochemically investigated regional numbers and tau isoforms of NFT in the hippocampal area of nine LNTD patients with anti-three-repeat (3R) tau-specific and anti-four-repeat (4R) tau-specific antibodies, differentiating NFT into three developmental stages of pretangles (PT), NFT and ghost tangles (GT). Consequently, most PT were 4R tau-positive, most GT were 3R tau-positive, and NFT were 3R tau-, 4R tau- or double-positive, suggesting that composition of tau isoforms may shift from a 4R tau-predominant pattern to a 3R tau-predominant pattern during the development of NFT. In addition, a large number of NFT showing different developmental stages and different rates of 3R tau- and 4R tau-positive neurons according to the region were found in the hippocampal area, suggesting that regions undergoing earlier NFT formation may show higher ratio of 3R tau-positive neurons to 4R tau-positive neurons, and that NFT formation may begin in the entorhinal and transentorhinal cortices, subsequently progress to the subiculum and CA1, and further to the CA2, amygdala and CA3-4, although progression to the neocortex is limited. Furthermore, 4R tau-positive astrocytes and grains were found in several patients, suggesting that LNTD is a form of tauopathy.     

Evaluation of subjective treatment satisfaction with antipsychotics in schizophrenia patients

Adherence to antipsychotic treatment is particularly important in the long-term management of schizophrenia and other related psychotic disorders since poor adherence to medication is associated with poor health outcomes. Although the patients' subjective satisfaction with the medication is crucial for adherence to medication, few studies have examined the relationship between subjective satisfaction with antipsychotics and adherence. In this study, we investigated subjective satisfaction with antipsychotics in patients with schizophrenia by using the Treatment Satisfaction Questionnaire for Medication (TSQM), a self-reporting instrument to assess the major dimensions of patients' satisfaction with their medication. The subjects included 121 clinically stabilized outpatients who met the following criteria: 1) patients between 20 and 65 years of age, diagnosed with schizophrenia or other psychotic disorders as defined by DSM-IV, 2) patients undergoing oral antipsychotic monotherapy or taking only an antiparkinsonian agent as an adjuvant remedy, and 3) patients who had received a stable dose of an antipsychotic for more than four weeks. Patients were asked to answer the TSQM questions, and their clinical symptoms were also evaluated by the Brief Psychiatric Rating Scale (BPRS). Satisfaction with regard to side-effects (p=0.015) and global satisfaction (p=0.035) were significantly higher in patients taking second-generation antipsychotics (SGAs, n=111) than those taking first-generation antipsychotics (FGAs, n=10), whereas no significant difference was found between the two groups in clinical symptoms according to BPRS (p=0.637) or the Drug-induced Extrapyramidal Symptoms Scale (DIEPSS, p=0.209). In addition, correlations were not significant between the subjective satisfactions and clinician-rated objective measures of the symptoms. These findings suggest that SGAs have more favorable subjective satisfaction profiles than FGAs in the treatment of schizophrenia. Since it is often difficult to detect the difference by a traditional objective assessment of the patients, it is desirable that physicians pay attention to the patients' subjective satisfaction in conjunction with their own objective clinical assessment.     

In the absence of a basal lamina,ameloblasts absorb enamel in a serumless and chemically defined organ culture system

ObjectivesTooth organ development was examined in a serumless, chemically defined organ culture system to determine whether morphological and functional development was identical to that in in vivo and serum-supplemented organ cultures.MethodsMouse mandibular first molar tooth organs at 16 days of gestation were cultured for up to 28 days in a Tronwell culture system using a serum-supplemented or serumless, chemically defined medium. After culture, specimens were processed for assessing tooth development using ultrastructural, immunohistochemical, and mRNA expression analyses.ResultsIn serum-supplemented conditions, inner enamel epithelial cells differentiated into secretory-stage ameloblasts, which formed enamel and reached the maturation stage after 14 and 21 days of culture, respectively. Ameloblasts deposited a basal lamina on immature enamel. Conversely, in serumless conditions, ameloblasts formed enamel on mineralized dentin after 21 days. Moreover, maturation-stage ameloblasts did not form basal lamina and directly absorbed mineralized enamel after 28 days of culture. RT-PCR analysis indicated that tooth organs, cultured in serumless conditions for 28 days, had significantly reduced expression levels of ODAM, amelotin, and laminin-322.ConclusionsThese results indicate that several differences were detected compared to the development in serum-supplemented conditions, such as delayed enamel and dentin formation and the failure of maturation-stage ameloblasts to form basal laminae. Therefore, our results suggest that some factors might be required for the steady formation of mineralized dentin, enamel, and a basal lamina. Additionally, our results indicate that a basal lamina is necessary for enamel maturation.     

Gray matter lesions in Nasu‐Hakola disease: A report on three autopsy cases

Nasu‐Hakola disease is an autosomal recessively inherited disease characterized by lipomembranous polycystic osteodysplasia and sclerosing leukoencephalopathy. While white matter lesions prominent in the brain have been reported in the literature, gray matter lesions have not received particular attention. In this study, we examined three autopsy cases of Nasu‐Hakola disease in order to focus specifically on gray matter lesions. The ages at onset of the three cases were 20, 23 and 29 years, and the disease durations were 29, 19 and 8 years, respectively. In addition to characteristic degeneration in the cerebral white matter, such as demyelination with conspicuous fibrillary gliosis and axonal changes, all three cases showed overt pathology in the gray matter. Neuronal loss with gliosis in the thalamus (particularly in the dorsomedial nucleus and anterior nucleus), caudate nucleus, putamen and substantia nigra was prominent in all cases, and the severity corresponded to the disease duration. The cerebral cortices were relatively preserved in all cases. One case showed neuronal loss and gliosis in the gray matter of the hippocampus, possibly due to repeated episodes of epileptic convulsions. These gray matter pathologies are considered to be responsible for some of the clinical manifestations of the disease, including extrapyramidal symptoms.     

Distribution of cerebral amyloid deposition and its relevance to clinical phenotype in Lewy body dementia

Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) are clinically distinguished based only on the duration of parkinsonism prior to dementia. It is known that there is considerable pathological overlap between these two conditions, but the pathological difference between them remains unknown. We evaluated Alzheimer-type pathology in 30 brains of patients with Lewy body dementia using standardized methods based on those of the Brain-Net Europe (BNE) Consortium. Only 2 of 13 PDD cases (15%) showed Aβ-immunoreactive pathology in the midbrain (amyloid phase IV). In contrast, 12 of 17 DLB cases (71%) exhibited midbrain involvement. Four of the DLB cases (24%) but none of the PDD cases exhibited Aβ-immunoreactive pathology in the cerebellum (amyloid phase V). The ratio of cases with subtentorial involvement of amyloid deposition was significantly higher in DLB than in PDD. The median of amyloid phases was significantly greater in DLB than in PDD, but there was no difference in neurofibrillary tangle (NFT) Braak stages or in Lewy body scores. When patients were classified according to whether dementia or parkinsonism had occurred first, the rate of dementia having occurred first was significantly greater in amyloid phase IV and V than in phase 0–I, with phase III in the middle, though there was no significant difference in median NFT Braak stage or mean Lewy body score associated with amyloid phase. These results suggest that amyloid deposition may contribute to the timing of the onset of dementia relative to that of parkinsonism in Lewy body dementia.