1,720,962 research outputs found
Cholinergic innervation of pial arteries in senescent rats: an immunohistochemical study.
No full textPerivascular acetylcholine (ACh)-immunoreactive nerve fibres were demonstrated in basilar and middle cerebral arteries, in pial arteries and arterioles and in intracerebral arteries of male Fisher 344 rats of 6 months (young), 15 months (adult) and 22 months (senescent). Analysis included whole mounts of basilar and middle cerebral arteries, of pial arteries and sections of brain including pia-arachnoid membrane to demonstrate the localization of nerve fibres throughout the wall of pial and of intracerebral arteries. ACh-immunoreactive nerve fibres were demonstrated by indirect immunohistochemistry using a polyclonal anti-ACh antibody and their relative density was quantified. Perivascular ACh-immunoreactive nerve fibres were located in basilar and middle cerebral arteries, in pial arteries and arterioles and in intracerebral arteries. These fibres were found in the adventitia and adventitia-media border with a higher density in pial rather than in intracerebral arteries. A decrease of ACh-immunoreactive nerve fibres was observed both in pial and intracerebral arteries of adult or senescent rats compared to younger cohorts. The direct demonstration of ACh-immunoreactive nerve fibres in the cerebrovascular tree may contribute to evaluate the influence of experimental and pathological conditions on cerebrovascular cholinergic neuroeffector mechanisms, including a role of cholinergic innervation in the pathophysiology of cerebrovascular disease of the elderly
Immunochemical and immunocytochemical characterization of cholinergic markers in human peripheral blood lymphocytes.
No full textCholinergic markers and the expression of M(2)-M(5) muscarinic cholinergic receptor subtypes were investigated in human peripheral blood lymphocytes by Western blot analysis and immunocytochemistry. The totality of peripheral blood lymphocytes express acetylcholine (ACh) immunoreactivity, choline acetyltransferase (ChAT), acetylcholinesterase (AChE), vesicular ACh transporter (VAChT) and M(2)-M(5) muscarinic cholinergic receptor protein immunoreactivity. Western blot analysis performed independently on T and B lymphocytes using anti-ChAT and anti-AChE antibodies revealed labelling of single bands of approximately 68-70 and 70 kDa, respectively, whereas VAChT was bound to two bands of approximately 80 and 45 kDa. The pattern of immunoblotting was similar in membranes of lymphocytes and striatum, used as a reference brain tissue. Western blot analysis using anti M(2)-M(5) receptor antibodies revealed labelling of single bands of approximately 55, 85-90, 50 and 81 kDa, respectively. Confocal laser immunofluorescence showed the localization of ACh and VAChT immunoreactivity in punctiform areas likely corresponding to cytoplasmic vesicles. ChAT and AChE were diffused to the cytoplasm and plasma membrane. Muscarinic receptor immunoreactivity was located in lymphocyte plasma membrane. Although the role of lymphocyte cholinergic system is still unclear, the demonstration of cholinergic markers in T and B human blood lymphocytes supports the view that a cholinergic systems may contribute to the regulation of immune function. The characterization of these cholinergic markers may also contribute to define if their evaluation can be used for assessing the status of brain cholinergic system
Muscarinic cholinergic receptor subtypes in the hippocampus of aged rats.
No full textIn spite of the suggestion of impaired muscarinic function in adult-onset cognitive disorders, data on the expression of muscarinic receptors in the hippocampus as a function of age are inconsistent. One reason may be that the majority of investigations were unable to differentiate the five brain muscarinic receptors subtypes. In this study, using a protocol based on a combination of both kinetic and equilibrium binding approaches, we have assessed the expression and the density of M1-M5 muscarinic cholinergic receptors in the hippocampus of Fisher 344 rats aged 6, 15 and 22 months. An age-related decrease of the density of M1 receptor was found in pyramidal neurons of the CA1 subfield. In this area, other subtypes of muscarinic receptors were unchanged with the exception of a loss of M2 receptor in the radial layer. In the CA3 subfield, receptor changes involved M2, M3 and M5 subtypes, whereas in the dentate gyrus, the main changes affected M1 and M2 receptors of the granular layer and M2 and M3 receptors of the molecular layer. The above findings indicate that analysis of age-related changes of different muscarinic cholinergic receptors might represent a useful contribution to identifying the basis of cholinergic neurotransmission impairment in adult-onset cognitive dysfunction
Peripheral blood lymphocytes muscarinic cholinergic receptor subtypes in Alzheimer's disease: a marker of cholinergic dysfunction?
No full textMuscarinic M2-M5 muscarinic cholinergic receptors were investigated in peripheral blood lymphocytes of patients with mild cognitive impairment of the Alzheimer's type (MCIAT), probable Alzheimer's disease (AD) and probable vascular dementia (VaD). [3H]-N-methyl scopolamine (NMS) in the presence of muscarinic antagonists and Mamba venom to occlude different receptor subtypes was used as radioligand. Analysis of [3H]-NMS binding curves without receptor subtype assessment resulted in a slight decrease of receptor density in AD patients. Evaluation of receptor subtypes in MCIAT and AD patients revealed a decrease of M3 receptor by more than 50%, an increase of M4 receptor expression by about 20% and no changes of M2 or M5 receptors. The expression of M2-M5 receptors was unaltered in VaD patients. Strong positive and negative correlations respectively were found between the density of lymphocyte M3 and M4 receptors and MMSE score in both MCIAT (0.78 for M3 receptor and 0.80 for M4 receptor) and AD (0.82 for M3 receptor and 0.83 for M4 receptor) patients. These findings suggest that changes in the expression of peripheral blood lymphocyte M3 and M4 receptors in AD are related to the degree of cognitive impairment. Assessment of lymphocyte muscarinic receptor subtypes may contribute to characterization of cholinergic impairment in AD
Identification of dopamine plasma membrane and vesicular transporters in human peripheral blood lymphocytes.
No full textIF 3,35
Peripheral blood lymphocytes muscarinic cholinergic receptor subtypes in Alzheimer's disease: a marker of cholinergic dysfunction?
No full textIF 3,35
Identification of dopamine plasma membrane and vesicular transporters in human peripheral blood lymphocytes
No full textPlasma membrane dopamine transporter (DAT), vesicular monoamine transporters (VMAT) type-1 and -2 and the expression of the dopaminergic markers dopamine and tyrosine hydroxylase were assessed in membranes and/or in cytospin centrifuged human peripheral blood lymphocytes. The radiolabeled DAT ligand [3H]GBR12935 was bound to peripheral lymphocytes in a manner consistent with the specific binding to a dopamine uptake system, with a dissociation constant similar to that found in striatum, but with a lower density of binding sites. On the other hand, no specific binding occurred in cerebellum used as a test tissue not expressing DAT. Western blot analysis using antibodies raised against amino or carboxy terminus of DAT or against VMAT-1 or VMAT-2 revealed labeling of single bands of approximately 76, 55 or 68 KDa, respectively, displaying similar migration characteristics in lymphocytes and test tissues used for comparison. Immunofluorescence revealed that anti-dopamine, anti-tyrosine hydroxylase, anti-DAT, anti-VMAT-1 and anti-VMAT-2 antibodies labeled the total population of cytospin-centrifuged lymphocytes mounted on microscope slides. Confocal laser microscopy demonstrated that dopamine and VMAT-2 immunoreactivity was developed mainly in cytoplasmic punctiform areas likely corresponding to vesicles and to a lower extent was associated to plasma membrane. Tyrosine hydroxylase immunoreactivity was diffused to cytoplasm and to plasma membrane of lymphocytes, whereas DAT and VMAT-1 immunoreactivity were located almost exclusively in lymphocyte plasma membrane and cytoplasm, respectively. Lymphocyte DAT characterized in this study has probably functional relevance as [3H]dopamine was taken up by intact lymphocytes and uptake was inhibited specifically by compounds known to affect dopamine transport. These findings indicate that human peripheral blood lymphocytes possess DAT plasma membrane and VMAT-1 and VMAT-2 transporters. Increasing evidence indicates that dopamine transporter changes may be related to neuronal injury. In view of this assessment of lymphocyte DAT and VMAT transporters can be considered for identifying pathologies characterized by impaired dopaminergic neurotransmission
Peripheral blood lymphocytes muscarinic cholinergic receptor subtypes in Alzhimer’s disease: a marker of cholinergic dysfunction?
No full textInfluence of age L-type Ca2+ channels in the pulmonary artery and vein of spontaneously hypertensive rats
No full textThe influence of age on the density and localization of L-type Ca2+ channels was studied during development of hypertension in the pulmonary artery and vein of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats by radioligand binding assay and light microscope autoradiography. SHR were examined at 6 weeks (juvenile, pre-hypertensive stage), 12 weeks (young, developing hypertension) and 24 weeks (mature, established hypertension). The dihydropyridine-type Ca2+ antagonist [3H]nicardipine was used as a radioligand. It was bound specifically to sections of rat pulmonary artery and vein. Dissociation constant (Kd) values were similar in WKY rats and SHR, whereas maximum density of binding sites (Bmax) values increased in SHR in comparison with WKY rats. This increase was noticeable from the pre-hypertensive phase. The pharmacological profile of [3H]nicardipine binding was similar in different age groups of either normotensive and hypertensive rats. Quantitative analysis of autoradiographs from SHR revealed a progressive increase of silver grains in smooth muscle of tunica media and to a lesser extent in the adventitia of pulmonary artery but not of pulmonary vein from pre-hypertensive stage to developing hypertension. No further changes were observed in established hypertension. The above data indicate that the density of L-type Ca2+ channels of pulmonary arteries is increased in SHR. This augmentation after the pre-hypertensive phase suggests the occurrence of dysregulation of Ca2+ handling in the pulmonary vasculature of developing SHR
Influence of age on L-type Ca(2+) channels in the pulmonary artery and vein of spontaneously hypertensive rats
No full text- …
