UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

LONG DURATION VENTRAL ROOT POTENTIALS IN THE NEONATAL RAT SPINAL-CORD INVITRO - THE EFFECTS OF IONOTROPIC AND METABOTROPIC EXCITATORY AMINO-ACID RECEPTOR ANTAGONISTS

THOMPSON, SWN; GERBER, G; SIVILOTTI, LG; WOOLF, CJ; (1992) LONG DURATION VENTRAL ROOT POTENTIALS IN THE NEONATAL RAT SPINAL-CORD INVITRO - THE EFFECTS OF IONOTROPIC AND METABOTROPIC EXCITATORY AMINO-ACID RECEPTOR ANTAGONISTS. BRAIN RES , 595 (1) 87 - 97.

Full text not available from this repository.

Abstract

Long duration, primary afferent evoked ventral root potentials (VRP's) have been recorded in vitro from hemisected spinal cords prepared from 8-12-day-old rat pups. Single shock stimulation of a dorsal root at stimulus strengths sufficient to recruit C/group IV afferent fibres evoked a long duration (11.9 +/- 1.2 s) ipsilateral VRP in all preparations. This long duration VRP consisted of two components, (i) a slow wave, time to peak 137.0 +/- 5.1 ms, the amplitude of which was reduced to 8.7% of mean control value in the presence of the N-methyl-D-aspartate (NMDA) antagonis D-AP5 (40 muM), (ii) a prolonged wave with a time to peak of 2.0 +/- 0.2 s which was partially resistant to D-AP5 (40 muM). Both the slow and the prolonged waves were unaffected following superfusion with the metabotropic excitatory amino acid (EAA) receptor antagonist L-AP3 (100-200 muM). Low frequency (1-10 Hz) repetitive stimulation (20 s duration) of high threshold dorsal root afferents evoked a temporal summation of synaptic activity which generated a progressively depolarizing VRP. This cumulative VRP was graded with frequency of stimulation (0.89 +/- 0.13 to 1.25 +/- 19 mV). The cumulative VRP was followed by a post-stimulus depolarization which outlasted the period of repetitive stimulation by tens of seconds (47.6 +/- 8.4 to 91.2 +/- 19.9 s). In the presence of AP5 the amplitude of the cumulative VRP was depressed to 54.5 +/- 11.5% of control values when low frequency (1.0 Hz) stimulation was used. The proportion of the cumulative VRP resistant to D-AP5 increased as the frequency of stimulation was increased to 10 Hz. The decay time of the post-stimulus depolarization was unaffected by AP5. Neither the amplitude nor the post-stimulus depolarization of the cumulative VRP was affected by 200 muM L-AP3. It is suggested that both an AP5 sensitive and AP5 insensitive potential contribute to the long duration VRP evoked in the neonatal rat spinal cord following single shock high threshold afferent stimulation. Moreover, the AP5 insensitive prolonged depolarization is manifest following sustained low frequency stimuli and higher frequency inputs.

Type: Article
Title: LONG DURATION VENTRAL ROOT POTENTIALS IN THE NEONATAL RAT SPINAL-CORD INVITRO - THE EFFECTS OF IONOTROPIC AND METABOTROPIC EXCITATORY AMINO-ACID RECEPTOR ANTAGONISTS
Keywords: N-METHYL-D-ASPARTATE RECEPTOR, METABOTROPIC GLUTAMATE RECEPTOR, SLOW VENTRAL ROOT POTENTIAL, CUMULATIVE DEPOLARIZATION, DORSAL HORN NEURONS, STIMULATED PHOSPHOINOSITIDE HYDROLYSIS, SUBSTANTIA GELATINOSA NEURONS, GENE-RELATED PEPTIDE, HIPPOCAMPAL-NEURONS, SYNAPTIC TRANSMISSION, NEWBORN RAT, RESPONSES, INHIBITION, REFLEXES
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology
URI: http://discovery.ucl.ac.uk/id/eprint/57232
Downloads since deposit
0Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item