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The electrical properties of olfactory receptor neurons, enzymatically dissociated from the channel catfish (Ictalurus punctatus), were studied using the whole-cell patch-clamp technique. Six voltage-dependent ionic currents were isolated. Transient inward currents (0.1-1.7 nA) were observed in response to depolarizing voltage steps from a holding potential(More)
Olfactory transduction is thought to be mediated by a G protein-coupled increase in intracellular adenosine 3',5'-monophosphate (cAMP) that triggers the opening of cAMP-gated cation channels and results in depolarization of the plasma membrane of olfactory neurons. In olfactory neurons isolated from the channel catfish, Ictalurus punctatus, stimulation with(More)
Olfactory receptor neurons enzymatically dissociated from channel catfish olfactory epithelium were depolarized transiently following dialysis of IP3 or cAMP (added to the patch pipette) into the cytoplasm. Voltage and current responses to IP3 were blocked by ruthenium red, a blocker of an IP3-gated Ca(2+)-release channel in sarcoplasmic reticulum. In(More)
Olfactory neurons respond to odors with a change in conductance that mediates an influx of cations including Ca2+. The concomitant increase in [Cai] has been postulated to play a role in the adaptation to maintained odorant stimulation (Kurahashi, T., and T. Shibuya. 1990. Brain Research. 515:261-268. Kramer, R. H., and S. A. Siegelbaum. 1992. Neuron.(More)
We have studied the spectral properties of the voltage-sensitive dye, 1-(3-sulfonatopropyl)-4-[beta [2-(di-n-octylamino)-6-naphtyl]vinyl] pyridinium betaine (di-8-ANEPPS), and the Ca(2+)-sensitive dye, fura-2, in azolectin liposomes and in isolated taste buds from mouse. We find that the fluorescence excitation spectra of di-8-ANEPPS and fura-2 are largely(More)
The sense of smell allows terrestrial animals to collect information about the chemical nature of their environment through the detection of airborne molecules. In humans smell is believed to play an important role in protecting the organism from environmental hazards such as fire, gas leaks and spoiled food, in determining the flavor of foods, and perhaps(More)
1. The effect of intracellular application of inositol 1,4,5-trisphosphate (IP3) from the patch pipette was analyzed in isolated rat olfactory neurons under whole-cell patch clamp. 2. Intracellular dialysis of 10 microM 1,4,5-IP3 in K(+)-internal solution induced a sustained depolarization of 35.8 +/- 10.5 (SD) mV (n = 16). The IP3-induced response was(More)
Membrane vesicles derived from external taste epithelia of channel catfish (Ictalurus punctatus) were incorporated into lipid bilayers on the tips of patch pipettes. Consistent with previous experiments (Teeter, J. H., J. G. Brand, and T. Kumazawa. 1990. Biophys. J. 58:253-259), micromolar (0.5-200 microM) concentrations of L-arginine (L-Arg), a potent(More)
Amino acids are important taste stimuli for a variety of animals. One animal model, the channel catfish, I. punctatus, possesses sensitive taste receptor systems for several amino acids. Neurophysiological and biochemical receptor binding studies suggest the presence of at least three receptor pathways: one is a relatively nonspecific site(s) responsive to(More)
Olfactory neurons from the channel catfish, Ictalurus punctatus, were isolated by a brief (15 min) treatment with papain. After incubation with fura-2 acetoxymethyl ester (fura-2/AM) for 1 h, the isolated olfactory receptor cells are found to hydrolyze fura-2/AM to fura-2 free acid without detectable traces of intermediate products of hydrolysis.(More)