Effects of 3,3-dipyridylmethyl-1-phenyl-2-indolinone on gamma-aminobutyric acid elicited chloride current of snail central neuron.
The effects of (1) gamma-aminobutyric acid (GABA) on the excitable membrane and (2) DPMPI (3,3-dipyridylmethyl-1-phenyl-2-indolinone) on the microperfused GABA elicited currents were investigated on central LP5 neuron of giant African snail, Achatina fulica Ferussac, with conventional voltage-clamp technique. GABA elicited an inward current of LP5 neuron by a concentration and voltage dependent manner. Muscimol, GABAA receptor agonist, did, while baclofen, GABAB receptor agonist, did not, elicit the membrane current on the neuron. The GABA elicited currents in LP5 neuron were blocked by picrotoxin, a GABAA receptor ion channel complex antagonist while the currents were not blocked by phaclofen, a GABAB receptor antagonist. The results suggested that the GABA elicited current in LP5 neuron was mainly due to activation of GABAA receptor. DPMPI increased the frequency of the spontaneously generated action potential of the neuron. In the voltage clamped neuron, DPMPI decreased the GABA elicited responses by a concentration dependent manner. DPMPI altered neither the reversal potential of GABA elicited current, nor the membrane resistance of the excitable membrane of central LP5 neuron. The results concluded that DPMPI altered the GABAA activated receptor ionic channel complex of the LP5 neuron.
Chen
Y H
YH
Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, ROC.
Cheng
C Y
CY
Huang
S S
SS
Tsai
M C
MC
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002490:Central Nervous System / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D004594:Electrophysiology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D017952:Ganglia, Invertebrate / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011725:Pyridines / Q000494:pharmacology*; D012908:Snails / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D018118:Chloride Channels; D018755:GABA Agonists; D018756:GABA Antagonists; D007211:Indoles; D011725:Pyridines; D005680:gamma-Aminobutyric Acid; C061017:linopirdine