Quisqualate-activated single channel currents in neuromuscular preparations of small and large crayfish.
Single channel currents elicited by 1-5 mumol/l quisqualate in neuromuscular preparations in large (greater than 16 month old) and small (1-3 month old) crayfish were recorded by means of the patch-clamp technique. In preparations from large crayfish single channel currents of variable amplitude (-1 to -12 pA) were induced by quisqualate. The mean burst lengths of these currents were tau approximately equal to 1-2 ms. In the opener muscle of the first walking leg and the contractor epimeralis muscle of small crayfish the mean burst lengths of single channel currents evoked by quisqualate were prolonged by a factor of about 4 (tau approximately equal to 5 ms). Moreover, in the opener muscle of the first walking leg of small crayfish single channel currents of small amplitude (-0.5 to -2.5 pA) were preferentially evoked by quisqualate. By contrast, in the contractor epimeralis muscle of small crayfish mainly single channel currents of large amplitude (-10 to -12 pA) were elicited by quisqualate. The results suggest that at the stage of neuromuscular development characterizing the small crayfish, gating properties of excitatory postsynaptic channels are different from those in adult crayfish. Furthermore, the results obtained in the opener muscle of the first walking leg of small crayfish are consistent with those obtained previously by means of the noise analysis technique.
Finger
W
W
Physiologisches Institut der Technischen Universität München, F.R.G.
Martin
C
C
Pareto
A
A
D000818:Animals; D003400:Astacoidea / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D010069:Oxadiazoles / Q000494:pharmacology*; D016318:Quisqualic Acid
D007473:Ion Channels; D010069:Oxadiazoles; D016318:Quisqualic Acid