Pearce, Rosalyn Joan; (1992) Electrophysiological and microfluorimetric studies of mouse dorsal root ganglion cells. Doctoral thesis (Ph.D), UCL (University College London).

Text Electrophysiological_and_micro.pdf Download (9MB)

Abstract

Primary sensory neurones consist of discrete functional groups, previously defined in terms of cell size and action potential shape. Whole cell patch clamp recordings were made from cells isolated from mouse dorsal root ganglia (DRGs) to define the ionic basis for these characteristics. Three groups emerged, expressing different arrays of voltage-activated currents. These correlated well with cell size, measured as a function of membrane capacitance. Capsaicin was used to identify a subset of small nociceptive cells. The properties of the major currents underlying the differences in electrophysiological behaviour of the cells were characterised. The cells were used to investigate the basis for altered neuronal function during hypoxia/anoxia. Microfluorimetric techniques were used to monitor: (i) intracellular calcium ([Ca2+]i) using indo-1 (ii) mitochondrial membrane potential (ψm) using Rhodamine 123 and (iii) the autofluorescence of mitochondrial NADH. Anoxia increased [Ca2+]i), depolarised ψm and increased autofluorescence. Blockade of mitochondrial electron transport by cyanide had equivalent effects. The pO2 sensitivity of these effects was defined. The baseline redox status of cells was estimated through measurement of maximal (blockade of oxygen consumption with CN/anoxia) and minimal autofluorescence (maximising oxygen consumption with uncoupler, FCCP). The contribution of the F1-F0 ATPase to ψm was studied using oligomycin. This revealed the reversal of the ATPase with anoxia, slowing the rate of depolarisation of ψm. The actions of the convulsant barbiturate CHEB were examined. It was found to inhibit electron transport at Complex I, and was more potent than other barbiturates. In a proportion of cells which did not correlate clearly with the classification described above, CHEB raised [Ca2+l]i dramatically. This was distinct from its metabolic effects, resulting from the opening of a non-selective cation conductance. This action could underlie the convulsant effect of the drug.

Download activity - last month

Export as XMLJSONCSV

Download activity - last 12 months

Export as CSVJSONXML

Downloads by country - last 12 months

Export as XMLJSONCSV

Archive Staff Only

View Item