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Home > Role of Muscarinic Receptors in Memory Retrieval

Role of Muscarinic Receptors in Memory Retrieval

Thesis Info

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Author

Rashid, Habiba

Program

PhD

Institute

National University of Sciences & Technology

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

2018

Thesis Completion Status

Completed

Subject

Bio sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/10757/1/Habiba%20Rashid_Applied_Biosciences_HSR_2018-NUST_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727120265

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Learning and memory is essential for successful survival of humans and animals. Memory retrieval is the phenomenon of utilizing memories and information acquired in the past to make decision and performance in present. It is crucial for survival and day to day activities of humans and animals. Inability to retrieve memories is known as retrograde amnesia. Cholinergic receptors are important for regulation of learning and memory processes. Impaired cholinergic transmission is a leading cause of cognitive deficit and amnesia. Cholinergic receptors, i.e. muscarinic and nicotinic receptors, have established role in memory acquisition and consolidation but their involvement in memory retrieval is not much investigated. This study was conducted to explore the role of muscarinic cholinergic receptors in memory retrieval and the effect of gender. Gender dependent role of muscarinic receptors in memory retrieval was assessed in young Balb/c mice under normal conditions, sub-chronic stress, post traumatic brain injury and sub-chronic D2 dopamine receptor antagonism. Mice were trained for spatial and fear memories, using Morris water maze test and contextual fear conditioning, respectively. After training they were subjected to cholinergic drug treatment i.e, 1mg/kg scopolamine (muscarinic receptor antagonist) and 1mg/kg donepezil (acetylcholine esterase inhibitor), under normal conditions, following sub-chronic restrain stress, traumatic brain injury and dopamine D2 receptor antagonism by risperidone (2.5 mg/kg). Memory retrieval was accessed using probe trial and context retention. Further, the involvement of hippocampal and entorhinal cortex muscarinic receptors in memory retrieval was also explored. Under normal conditions acute (30 minutes before test) and sub-chronic (for five days) muscarinic blockade impaired spatial memory retrieval in male (P < 0.05) but not in female mice (P > 0.05). Acute and sub-chronic scopolamine treatment impaired retrieval of contextual fear memory in male and female mice (P < 0.05), except sub-chronic treated female mice (P > 0.05). There was no effect of acute and sub-chronic cholinergic receptor antagonism on object memory retrieval in male and female mice. Sub-chronic stress impaired spatial memory retrieval in both male and female mice (P < 0.05) but the impaired spatial recall was not effected by muscarinic activity. However, muscarinic receptor activation by donepezil reversed stress induced fear memory retrieval in mice irrespective of gender (P < 0.005). Sub-chronic muscarinic modulation affected trauma induced neurological damage in gender dependent manner but their effect was not significant in reversing trauma induced fear and spatial memory retrieval deficit in both genders. Gender and task dependent effect of muscarinic receptors were observed in memory retrieval under sub-chronic dopamine antagonism. In male mice muscarinic modulation impaired spatial memory retrieval under dopaminergic antagonism (P < 0.05). Muscarinic antagonism impaired fear retrieval in males but significantly enhanced fear recall in females (P < 0.005) under sub-chronic antagonism. Hippocampal and medial entorhinal cortex muscarinic receptors were found to mediate spatial and fear memory retrieval but not the object memory retrieval. It is concluded that muscarinic receptors are important for memory retrieval. Under physiological conditions muscarinic activity displays gender dependent involvement in memory retrieval. Muscarinic activation enhanced emotional memory recall in both genders under stress condition. Sub-chronic muscarinic modulation gender dependently reversed trauma induced impaired spatial memory recall. Furthermore, muscarinic receptors in hippocampus and entorhinal are required for emotional and spatial memory retrieval. These findings suggest that role of muscarinic receptor activity in retrieving different types of memories depends on gender of subjects and the conditions during which memories are retrieved. Findings of this study emphasize on the importance of considering gender as crucial variable in exploring underlying mechanisms and potential therapeutic options for dementia and neurological disorders.
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پروفیسر مغنی تبسم

مظہر امام /پروفیسر شہریار/پروفیسر مغنی تبسم
افسوس اس ماہ فروری میں اردو کے آسماں پر درخشاں، چند ستاروں کے چھپ جانے سے اردو دنیا کی رونق میں کمی آگئی، جناب مظہر امام ، پروفیسر شہریار ، پروفیسر مغنی تبسم یکے بعد دیگرے رخصت ہوئے، مظہر امام کی شناخت آزاد غزل کے حوالے سے ہے، کئی شعری اور تنقیدی کتابوں کے مصنف تھے، پروفیسر شہریار اور پروفیسر مغنی تبسم، ہندوستان کی دو ممتاز جامعات یعنی مسلم یونیورسٹی اور جامعہ عثمانیہ میں اردو کے کامیاب اور نامور استاد ہی نہیں، شعرو ادب کی دنیا میں صاحب مرتبہ و مقام بھی تھے، شہریار کی شہرت گو ان کی زندگی کے دور آخر میں خوشبو کی طرح عام ہوئی لیکن نشاط غم اور رنج شادمانی کے مختصر اور فانی لمحات کا ساتھ عمر بھر رہا، ان کی شہرت کے شہپر جب سمٹے ہوئے تھے اس وقت بھی انہوں نے اس خاموشی کو بلیغ معانی دیے تھے، خواب، رات، دیار، پرچھائیں، سفر، تشنہ لبی کے پردے میں وہ دیار دل اور بزم دوستاں تلاش کرتے رہے، مغنی تبسم شہریار کے پیشہ تدریس میں ہی شریک نہیں رسالہ شعرو حکمت میں بھی برابر کے سہیم تھے، وہ حیدرآباد کے دائرہ ادبیات اردو اور رسالہ سب رس سے مدتوں وابستہ رہے، فانی بدایونی پر تحقیق کی تھی، درجنوں کتابیں لکھیں، عجیب بات ہے کہ ادبی سفر میں مغنی تبسم اور شہریار ساتھ ساتھ رہے، ابدی سفر میں بھی یہ رفاقت قائم رہی، شہریار کے نام ایک خط میں مغنی تبسم نے لکھا تھا کہ ’’شاعری تو ایسی چیز ہے جو خدا، انسان اور کائنات کے درمیان پچھلی راتوں کا دعائیہ بن جاتی ہے، کتنے لوگ ہیں جوان ساعتوں میں دست دعا دراز کرتے ہیں‘‘، مغفرت کے لیے کوئی عمل یا کوئی قول کام آسکتا ہے، ہمارا دست دعا بھی اسی لیے دراز ہے۔...

تبرکات نبوی ﷺکے انہدام سے متعلق حضرت عمر فاروق کی طرف منسوب روایت کا تحقیقی جائزہ

Almighty Allah has stated the nature of man that everything He loves towards the one He loves is dear to Him. For this reason, in every age human being has been attached to the remains of his beloved thing. The stories of the former Ummah are contained in the holy Qura᾽n, in which their remnants are proven to be safe after they passed away. This last Ummah also appears to meet these natural requirements. Therefore, just as this Ummah loves his Prophet (peace be upon him). Therefore the sacred Islamic ancient relics have extraordinary significance, which are attributed to the holy Prophet. Muslims get peace by them and kept protecting and persevering such relics during every period. The companions of the Prophet (PBUP) have kept them safe too and they organized particular arrangements for preserving them. But there is also a theory which those who believe these are considered as a prohibition of Islamic Sharia, and they present their arguments on the basis of a “Hadith” attributed to Ḥaḍrat ʻUmar Fārūq (R.A). It is narrated from Ḥaḍrat ʻUmar Fārūq, that the he used to give an importance to the memorandum of Muhammad (PBUH). In the light of such “Riwāyās”, the mentioned “Hadith” would be suspicious. It is essential that he research of this “Hadith” should be reviewed, how its status is? In this article, research has been studied by this “Hadith” that it is clear that this “Hadith” could not be narrated by Ḥaḍrat ʻUmar Fārūq (R.A). Therefore, the concept of demolition of such scared ancient relics could not be supported by the above mentioned “Hadith”.

Exploring the Role of School Leadership in Transforming the School into a Learning Community

School as a learning community is becoming one of the prominent notions in the contemporary efforts of transforming schools into learning centers where all the stakeholders are bounded together by a sense of belongingness and shared purpose of collective learning. A community, on this understanding is a group of people linked by a shared consciousness and shared identity where people are open and honest to each other because, they all see the world in the same way. Here, people develop a shared centre of values, sentiments and beliefs which encourages them to think in terms of "we" rather than "I". To transform a school into such a learning community the school leadership plays a critical role. The function of school leadership is growing complex and perplex in terms of its extensive involvement in the social, moral, educational and technical aspects of the school life. This leadership is considered as the entrance through which the norms, values and beliefs inter into the school milieu and become part of the school culture. Therefore, it becomes indispensable to explore the role of the principal as the school leader in transforming the school into a learning community. This study aimed at exploring the role of the school leadership in transforming a school into a learning community. It further intended to explore the strategies adopted by the school leadership and the challenges faced in transforming the school into a learning community. Within the qualitative research paradigm, the case study method was adopted to better meet the nature and requirements of the study. The research was conducted in a private secondary school in Karachi, Pakistan. The key research participant was the principal of the school whereas, the Vice-Principal, the Academic Coordinator, two subject coordinators, three teachers and a group of students and their parents were included as the secondary participants. This study revealed that the school leadership plays a multidimensional and complex role in creating a collegial school culture for the social, moral and educational development of the students. The school principal establishes collaborative relationships amongst all the stakeholders in order to transform the school into a learning community. He plays his role in providing opportunities for the teachers to enhance their professional growth and learning. Apart from the above, the principal also monitors the activities in order to ensure the effective achievement of targets and establish grounds for future review planning and establishing future target.