Glutamatergic neuromuscular transmission properties studied in single skeletal muscle fibers from adult honeybee
2007
Collet, Claude | Belzunces, Luc
Adult honeybee glutamatergic neuromuscular transmission properties have been explored at the macroscopic and single-channel level with the patch-clamp technique on single muscle fibers enzymatically isolated from metathoracic leg tibias. In the whole-cell configuration, dose-responses curves obtained with a computer-operated and pressure-driven fast perfusion system indicate that the two kinetically distinct components activated by L-glutamate have different affinity for the physiological agonist. Moreover, a component of the current, sustained throughout the perfusion with L-glutamate reverses close to 0 mV, while a fast inactivating component of the current reverses at more negative potentials. The glutamate channels agonists and antagonists classically known to affect neuromuscular transmission in skeletal muscle from other invertebrates (quisqualic acid, ibotenic acid and picrotoxin) were used to characterize the glutamatergic transmission pharmacology in honeybee. Single channel currents were also recorded from cell-attached and outside-out patches. The data obtained suggest that both qGluR and GluCl ion channels are present in the membrane of adult honeybee tibia muscle fibers. The single muscle fiber preparation described here provides a convenient way to study adult neuromuscular transmission in invertebrates, as well as its perturbation by pesticides targeting junctional or extrajunctional ionotropic glutamate receptors.
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