Interaction between gustatory depolarizing receptor potential and efferent-induced slow depolarizing synaptic potential in frog taste cell.
Electrical stimulation of parasympathetic nerve (PSN) efferent fibers in the glossopharyngeal nerve induced a slow depolarizing synaptic potential (DSP) in frog taste cells under hypoxia. The objective of this study is to examine the interaction between a gustatory depolarizing receptor potential (GDRP) and a slow DSP. The amplitude of slow DSP added to a tastant-induced GDRP of 10 mV was suppressed to 60% of control slow DSPs for NaCl and acetic acid stimulations, but to 20-30% for quinine-HCl (Q-HCl) and sucrose stimulations. On the other hand, when a GDRP was induced during a prolonged slow DSP, the amplitude of GDRPs induced by 1 M NaCl and 1 M sucrose was suppressed to 50% of controls, but that by 1 mM acetic acid and 10 mM Q-HCl unchanged. It is concluded that the interaction between GDRPs and efferent-induced slow DSPs in frog taste cells under hypoxia derives from the crosstalk between a gustatory receptor current across the receptive membrane and a slow depolarizing synaptic current across the proximal subsynaptic membrane of taste cells.
Sato
Toshihide
T
Division of Integrative Sensory Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8588, Japan. toshi@net.nagasaki-u.ac.jp
Nishishita
Kazuhisa
K
Okada
Yukio
Y
Toda
Kazuo
K
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004525:Efferent Pathways / Q000502:physiology; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D008526:Medulla Oblongata / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D011892:Rana catesbeiana; D011984:Sensory Receptor Cells / Q000502:physiology* / Q000648:ultrastructure; D013045:Species Specificity; D055366:Synaptic Potentials / Q000502:physiology*; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000166:cytology / Q000502:physiology*; D014059:Tongue / Q000166:cytology / Q000502:physiology*; D017833:Visceral Afferents / Q000502:physiology