eprintid: 10122318
rev_number: 8
eprint_status: archive
userid: 695
dir: disk0/10/12/23/18
datestamp: 2021-02-23 09:22:34
lastmod: 2021-02-23 09:22:34
status_changed: 2021-02-23 09:22:34
type: thesis
metadata_visibility: show
creators_name: Murphy, Kerry Peter Sean James
title: Long-term potentiation of transmission at neocortical synapses in slices of rat sensorimotor cortex and the involvement of NMDA receptors
ispublished: unpub
keywords: Biological sciences; Long-term potentiation
note: Thesis digitised by ProQuest.
abstract: 1. Long-term potentiation (LTP) is an enduring activity-dependent increase in synaptic efficacy which has been considered as a neural substrate for learning and memory. 2. LTP was induced in 22% of postsynaptic potentials (p.s.p.s) and 87% of field potentials evoked by stimulation of the subcortical white matter and recorded in layers III, V & VI of slices of adult rat sensorimotor cortex. Conditioning paradigms used were either high frequency stimulation of an afferent pathway or the repetitive pairing of an afferent volley with a postsynaptic injection of depolarizing current. Intracellularly recorded LTP was found to be input specific, homosynaptic and associative. 3. D-2-amino-5-phosphonopentanoic acid (AP5) was used to assess the involvement of N-methyl-D-aspartate (NMDA) receptors in neurotransmission and in the induction and expression of LTP in the neocortex. The majority of p.s.p.s (89%) and field potentials (80%) were mediated in part by NMDA receptors. A non-NMDA receptor mediated component always preceded a NMDA receptor mediated one. 4. AP5 blocked the induction of LTP in field potentials recorded in 5 out of 7 slices; following washout of AP5, a second, identical set of conditioning stimuli induced LTP. 5. AP5 applied 15-20 minutes after the induction of LTP, reduced the magnitude of potentiated field potentials in 13 out of 13 slices and 4 out of 4 potentiated p.s.p.s. A potentiated non-NMDA receptor mediated component preceded a potentiated NMDA receptor mediated one. 6. In most cases, the onset latency of the potentiated component of p.s.p.s was delayed by ~2ms after the onset of synaptic activity. This delay was not voltage-dependent. LTP appeared to be a property of intrinsic neocortical connections but not of the fastest conducting afferents, possibly arising from outside the neocortex.
date: 1991
oa_status: green
full_text_type: other
thesis_class: doctoral_open
thesis_award: Ph.D
language: eng
thesis_view: UCL_Thesis
primo: open
primo_central: open_green
verified: verified_manual
full_text_status: public
pages: 201
institution: UCL (University College London)
department: Physiology
thesis_type: Doctoral
citation:        Murphy, Kerry Peter Sean James;      (1991)    Long-term potentiation of transmission at neocortical synapses in slices of rat sensorimotor cortex and the involvement of NMDA receptors.                   Doctoral thesis  (Ph.D), UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10122318/1/Long-term_potential_of_transmi.pdf