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|Title:||ACETYL CHOLINE RECEPTOR M2 SUBTYPE DISTRIBUTION IN SPINAL CORD|
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|Authors/Affiliations:||1 Sherine Abdel Salam*; 1 Marie Moftah; 1 Ahmed Abdel Karim; |
1 Alexandria University, Zoology Department, Faculty of Science, Egypt
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|Content:||Acetylcholine (Ach) is the primary neurotransmitter secreted by efferent axons of the central nervous system which is responsible for all muscular movement. |
Cholinergic transmission is mediated via two different types of receptors, nicotinic and muscarinic. Within the nervous system, muscarinic receptors are present on some axon endings, regulating the neurotransmitter release.
The M2 subtype has been found to be one of the major muscarinic receptors expressed in the spinal cord as shown in several morphological studies. It has been implied in the regulation of spinal cord functions. Many pharmacological studies indicate that blockade of M2AchR by its antagonist results in significant cognitive improvement in the brain.
The most common outcome of traumatic injuries to spinal cord and brain in adult mammals, including humans, is significant tissue loss. This loss leads to crippling conditions since, once neural tissue is lost, it cannot be replaced because of the apparently limited ability of the mammalian central nervous system to repair itself.
Regeneration of the adult nervous system occurs efficiently in a limited number of vertebrates, such as fish and amphibians, and even within these groups, significant differences in regenerative capability have been reported. Moreover, Ach is known to be involved in the function of spinal locomotor networks in several vertebrate preparations. Therefore, it could have a crucial role in locomotion restoration after complete spinal cord transection and during its regeneration.
Consequently, my study will attempt to answer two main questions. The first would be whether the muscarinic receptor M2 subtype exists and is evenly or differentially distributed in spinal cord on motoneurons? This will be investigated in two different Vertebrate classes, namely Amphibians (Urodeles) and Mammals (mice) representing the two extremes of the regenerative capacity. The second question is whether M2AchR has a functional role during spinal cord regeneration and locomotion activity recuperation after spinal cord lesion. My preliminary results showed the precise intracellular localization of M2 receptors in spinal cord, immunocytochemistry was performed using a specific antibody targeting this receptor. A retrograde tracing technique was used in order to identify motoneurons. Consequently, following spinal cord lesion, my studies will focus on detecting the regeneration process and investigating the role expected to be played by M2AchR.
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