PERSISTENCE OF THE OLFACTORY RECEPTOR CURRENT IN A WIDE VARIETY OF
EXTRACELLULAR ENVIRONMENTS.
Kleene, Steven J. and Raymund Y.K. Pun.
Department of Cell Biology, Neurobiology and Anatomy and Department of
Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
45267-0521, USA.
APStracts 2:0369N, 1995.
SUMMARY AND CONCLUSIONS
1. We measured the current activated by cytoplasmic adenosine 3':5'-cyclic
monophosphate (cAMP) in olfactory cilia from the frog Rana pipiens. The
odorant-induced current in frog olfactory receptor neurons was also measured
for comparison. In both cases, recordings were done near the neuronal resting
potential in a variety of extracellular bath solutions. 2. In CaS2+S-free
baths, cAMP activated an inward current in excised olfactory cilia that was
carried entirely by cations. As extracellular CaS2+S was increased, the
cationic current decreased while a second current, carried by ClS-S,
increased. Total cAMP-activated current decreased with increasing
extracellular CaS2+S. When external NaS+S but not CaS2+S was eliminated, only
the ClS-S component of the current persisted. When external NaS+S and CaS2+S
were both removed, there was no cAMP-activated current. 3. In receptor
neurons, the total odorant-induced receptor current varied in a similar way
with the extracellular ionic environment. Under conditions favoring the
anionic receptor current, the response amplitude decreased and the latency
increased. 4. It is known that olfactory receptor currents persist in a wide
variety of extracellular environments. This persistence can be sufficiently
explained by the balance between cationic and anionic currents demonstrated
here.
Received 18 August 1995; accepted in final form 17 October 1995.
APS Manuscript Number J546-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95