Characteristics of GABA receptors on the ocellar L-neurons of American cockroach Periplaneta americana

Ming Chung Lee, Ji Chuu Hwang, Jin Tun Lin, Li Chu Tung

Research output: Contribution to journalArticle

Abstract

The ocellar L-neurons of cockroach Periplaneta americana were used in the present study as model systems to investigate the pharmacological properties of the GABA receptors. To do so, a glass microelectrode was impaled into the axon of the L-neurons to record the membrane potential intracellularly and to monitor membrane response to GABA treatment and cercal stimulation by air puff. The traditional GABA and their receptor agonists were introduced through perfusion and/or iontophoresis to monitor their effects on the L-neurons. The GABA receptor antagonists were administered by perfusion to examine if the response of the L-neurons to GABA and/or cercal stimulation was changed. The results revealed that administration of GABA, muscimol and imidazole acetic acid, two GABA A agonists, produced depolarization on the L-neurons. However, treatment of 3-APS and guanidine acetic acid, another two GABA A agonists, evoked hyperpolarization on the L-neurons. Among those tested antagonists, only picrotoxin, GABA A antagonist, antagonize the depolarization induced by GABA and/or cercal stimulation. More interestingly, administration of strychnine, glycine receptor antagonist, largely attenuated the depolarization response of the L-neurons to cercal stimulation. This attenuation caused by strychnine was even stronger than that initiated by varied GABA antagonists. In addition, phaclofen, a GABA B receptor antagonist, showed no antagonistic effect. These results strongly suggest that the characteristics of GABA receptors of the ocellar L-neurons may differ from those in vertebrates. It may be more likely to be a novel GABA receptor.

Original languageEnglish
Pages (from-to)178-186
Number of pages9
JournalChinese Journal of Physiology
Volume50
Issue number4
Publication statusPublished - 2007 Jan 1

Keywords

  • GABA receptors
  • Intracellular recording
  • Iontophoresis
  • Ocellar L-neurons
  • Periplaneta americana

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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