Hippocampus cholinergic innervation

Bouijeily N, Suszkiw JB. 1997. Developmental cholinotoxicity of lead loss of septal cholinergic neurons and long-term changes in cholinergic innervation of the hippocampus in perinatally lead-exposed rats. Brain Res 771(2) 319-328. 

Frotscher M, Leranth C. 1985. Cholinergic innervation of the rat hippocampus as revealed by choline acetyltransferase immunocytochemistry a combined light and electron microscopic study. J Comp Neurol 239(2) 237-246. 

Geula, C. (1998) Abnormalities of neural circuitry in Alzheimer s disease hippocampus and cortical cholinergic innervation, hieu-rology 51 S18—S29 discussion S65-67. 

Lewis, P. R., Shute, C. C. D. and Silver, A. (1967) Confirmation from choline acetylase analyses of a massive cholinergic innervation to the rat hippocampus. J. Physiol. (Lond.), 191, 215-224. 

Actions of acetylcholine (ACh) are referred to as muscarinic based on the observation that muscarine acts selectively at certain sites and, quahtatively, produces the same effects as ACh. Peripheral muscarinic acetylcholine receptors are found primarily on autonomic effector cells innervated by postganghonic parasympathetic nerves and on some cells that receive little or no cholinergic innervation but express muscarinic receptors e.g., vascular endothelial cells). There are also muscarinic receptors in ganglia and the adrenal meduUa, where muscarinic stimulation seems to modulate the effects of nicotinic stimulation. Within the central nervous system (CNS), the hippocampus, cortex, and thalamus have high densities of muscarinic receptors. 

Cortical and hippocampal pyramidal cells are noteworthy in at least three ways (1) they are preferentially, but not exclusively, innervated by cholinergic terminals (2) they are implicated as a potential site of consciousness and (3) they are enriched with cytoskeletal proteins, some of which undergo hyperphosphorylation in Alzheimer s disease. A novel signal transduction mode may exist within the large pyramidal cells of the cerebral cortex and hippocampus. 

The brain of AD patients is also characterized by the degeneration of basal forebrain cholinergic neurons, which innervates central regions involved in cognitive functions such as the cortex amygdala and hippocampus (1,3). The decline of cortical cholinergic activity as measured in postmortem brains... 

Gerfen, 2004). The patch compartments of the striatum are characterized by low levels of acetylcholine and high levels of various opiates and substance P. The matrix compartment is characterized by cholinergic and somatostatin-containing neurons. Anatomically, corticostriatal and thalamostriatal projections are closely associated with the striatal matrix, while projections from limbic structures, such as the hippocampus and the amygdala, primarily innervate striatal patches. 

Interruption of the septal hippocampal tract and elimination thereby of cholinergic afferencs to the hippocampus reduced by about 70Z the activity of choline acetyltransferase In homogenates of the hippocampus, but did not alter the binding of [3h]BZ by particles of such homogenates (8). The investigators proposed that presynaptlc muscarinic sites that are innervated by Che septal hippocampal nerve fibers do not bind the labeled benzilate, whereas postsynapclc muscarinic sites do bind It. 

Atropine blocks muscarinic cholinergic receptor competitively and has a large spectrum of clinical applications. Atropine acts as a parasympatholytic on parasymphathetically innerved organs. Therefore, the possible applications of atropine are as a general anesthetic and include its pure form or as a component. Brucine and other snake compounds interact with muscarinic acetylcholine receptors, and they are used in several types of clinical experiments, especially in autoradiography of the hippocampus in Alzheimer patients. ... 

Nadler and Cuthbertson (1980) have examined the effects of prior transection of hippocampal pathways on the pattern of neural vulnerability to kainic acid. Lesion of the entorhinal- (Kohler et al, 1978) or septo-hippocampal pathways protects dentate granule cells and most of the CA1 pyramidal cells from the neurotoxic effects of kainate injected into the hippocampus three days after the lesion. When both pathways are interrupted, the CA2 pyramidal cells also survive. However, disruption of the mossy fiber or commisural innervation to the hippocampus does not attenuate kainate s neurotoxicity on the hippocampal pyramidal cells. Notably, septal lesions that ablate the cell bodies of origin of the cholinergic... 

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