Comparative immunohistochemical study of the effects of pilocarpine on the mossy cells, mossy fibres and inhibitory neurones in murine dentate gyrus.
نویسندگان
چکیده
Treatment with pilocarpine (PILO) induces variable degrees of loss of mossy cells (MCs) and mossy fibre (MF) sprouting in rodents, the relationships of which have not been examined in individual animals. Our aim was to test whether the loss of MCs and MF sprouting are coupled processes in PILO-treated rodents. Animals which exhibited intense PILO-induced convulsions for at least 30 min were used in this study. After a 2-month survival period, the incidence of epileptic seizures was checked individually by neuropeptide-Y (NPY) immunohistochemistry, and the numbers of MCs were counted by means of immunohistochemistry, for calretinin (CR) in mice and calcitonin gene-related peptide (CGRP) in rats. MF sprouting was checked by using Timm's silver-sulphide method for zinc. In our comparative studies, NPY immunohistochemistry resulted in more positive animals than on zinc staining. The CR immunoreactivity remained unchanged even in those mice that displayed MF sprouting and greatly increased NPY immunoreactivity. CR immunoreactivity was also verified after transection of the fornix to exclude the extrahippocampal source of this peptide. However, the CGRP immunoreactivity was severely reduced in those rats that exhibited simultaneous increases in zinc content and NPY immunoreactivity in the supragranular layer and stratum lucidum. Our findings suggest that the MCs survive PILO treatment in mice, but not in rats. There is direct evidence of a close relationship between the loss of MCs and MF sprouting in rats, but not in mice. Thus, similar PILO seizures may result from different changes in the neuronal circuits of rodents.
منابع مشابه
Stress-related effects on neuronal morphology and choline acetyltransferase activity in the hippocampus
The effects of semi-chronic stress on neuronal morphology and choline acetyltransferase were studied by injecting rats with dexamethasone. It was found that in the dexamethasone-treated rats the choline acetyltransferase activity had increased in the area where the fibers from the perforant pathway synapse with the granular cell layer of the dentate gyrus and also where the mossy fibers of the ...
متن کاملStress-related effects on neuronal morphology and choline acetyltransferase activity in the hippocampus
The effects of semi-chronic stress on neuronal morphology and choline acetyltransferase were studied by injecting rats with dexamethasone. It was found that in the dexamethasone-treated rats the choline acetyltransferase activity had increased in the area where the fibers from the perforant pathway synapse with the granular cell layer of the dentate gyrus and also where the mossy fibers of the ...
متن کاملCombined Role of Seizure-Induced Dendritic Morphology Alterations and Spine Loss in Newborn Granule Cells with Mossy Fiber Sprouting on the Hyperexcitability of a Computer Model of the Dentate Gyrus
Temporal lobe epilepsy strongly affects hippocampal dentate gyrus granule cells morphology. These cells exhibit seizure-induced anatomical alterations including mossy fiber sprouting, changes in the apical and basal dendritic tree and suffer substantial dendritic spine loss. The effect of some of these changes on the hyperexcitability of the dentate gyrus has been widely studied. For example, m...
متن کاملRole of mossy fiber sprouting and mossy cell loss in hyperexcitability: a network model of the dentate gyrus incorporating cell types and axonal topography.
Mossy cell loss and mossy fiber sprouting are two characteristic consequences of repeated seizures and head trauma. However, their precise contributions to the hyperexcitable state are not well understood. Because it is difficult, and frequently impossible, to independently examine using experimental techniques whether it is the loss of mossy cells or the sprouting of mossy fibers that leads to...
متن کاملSpontaneous excitatory currents and kappa-opioid receptor inhibition in dentate gyrus are increased in the rat pilocarpine model of temporal lobe epilepsy.
Temporal lobe epilepsy is associated with a characteristic pattern of synaptic reorganization in the hippocampal formation, consisting of neuronal loss and aberrant growth of mossy fiber collaterals into the dentate gyrus inner molecular layer. We have used the rat pilocarpine model of temporal lobe epilepsy to study the functional consequences of mossy fiber sprouting on excitatory activity an...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Acta neurobiologiae experimentalis
دوره 75 2 شماره
صفحات -
تاریخ انتشار 2015