TY - JOUR
T1 - Rapid activation and desensitization by glutamate of excitatory, cation-selective channels in locust muscle
AU - Dudel, Josef
AU - Franke, Christian
AU - Hatt, Hanns
AU - Ramsey, Robert L.
AU - Usherwood, Peter N.R.
N1 - Funding Information:
Th~s work was supported by the Deutsche Forschungsgememschafl (SFB 220) We want to thank Miss Bettlna Winch for technical assistance and Mrs Martlna Grlessl for secretarial help t lg 2 Recordings and e~aluatlons ol single channel currents from an outside-out patch containing than= nels exhibiting brmt openings only I0 ~ M l-glutamate ,,~as apphed by hqmd hlament switch lor 20 ms A single traces digitized at 50 kHz filtered at It) kH7 Single channel amphtude IS pA B ~.urrcnl a~erage tot 187 traces ( distribution ol channel open times bm width 25 l*s Exponential scale ol e~ents bm as m Pig I( ~ The distribution is hired approxlmatel~ b'~ a single exponential v, llh llmt. conslant v = S0 Its although a second component may N. present
PY - 1988/5/16
Y1 - 1988/5/16
N2 - Outside-out patches of membrane were excised from extensor tibiae muscles of locusts. l-Glutamate or its agonists were applied to such patches in short pulses by means of a liquid filament switch. Cation-selective, excitatory channels were activated by quisqualate, l-glutamate and aspartate (in decreasing order of effectivity), but not by ibotenate, kainate, N-methyl-d-aspartate and glycine. At high agonist concentrations, channel activation reached a peak within 1 ms. Two kinetic types of channels have been identified: L-channels with on average relatively long and S-channels with short openings. Both types of channel openings showed surprisingly high rates of desensitization, channel activity declining after the initial surge to zero with time constants of about 25 and 3 ms, respectively. The L-channels exhibit open times close to those of channels recorded in MΩ-seal studies. The S-channel has not been reported previously.
AB - Outside-out patches of membrane were excised from extensor tibiae muscles of locusts. l-Glutamate or its agonists were applied to such patches in short pulses by means of a liquid filament switch. Cation-selective, excitatory channels were activated by quisqualate, l-glutamate and aspartate (in decreasing order of effectivity), but not by ibotenate, kainate, N-methyl-d-aspartate and glycine. At high agonist concentrations, channel activation reached a peak within 1 ms. Two kinetic types of channels have been identified: L-channels with on average relatively long and S-channels with short openings. Both types of channel openings showed surprisingly high rates of desensitization, channel activity declining after the initial surge to zero with time constants of about 25 and 3 ms, respectively. The L-channels exhibit open times close to those of channels recorded in MΩ-seal studies. The S-channel has not been reported previously.
KW - Excitatory membrane channel
KW - Locust muscle
KW - Outside-out patch
KW - Rapid desensitization
KW - l-Glutamate pulse
UR - https://www.scopus.com/pages/publications/0023893037
U2 - 10.1016/0304-3940(88)90311-4
DO - 10.1016/0304-3940(88)90311-4
M3 - Article
C2 - 2456491
AN - SCOPUS:0023893037
SN - 0304-3940
VL - 88
SP - 33
EP - 38
JO - Neuroscience Letters
JF - Neuroscience Letters
IS - 1
ER -