scholarly journals Action potentials initiated by single channels opening in a small neuron (rat olfactory receptor)

1989 ◽  
Vol 55 (4) ◽  
pp. 755-768 ◽  
Author(s):  
J.W. Lynch ◽  
P.H. Barry
Keyword(s):  
Olfactory Receptor ◽  
Action Potentials ◽  
Single Channels ◽  
Small Neuron

Electrophysiological models of the human pancreatic δ‐cell: From single channels to the firing of action potentials

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Gerardo J. Félix‐Martínez ◽  
Virginia González‐Vélez ◽  
J. Rafael Godínez‐Fernández ◽  
Amparo Gil
Keyword(s):  
Action Potentials ◽  
Single Channels

In vivo responses of single olfactory receptor neurons in the channel catfish, Ictalurus punctatus

1995 ◽  
Vol 73 (1) ◽  
pp. 172-177 ◽  
Author(s):  
J. Kang ◽  
J. Caprio
Keyword(s):  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Olfactory Receptor Neurons ◽  
Receptor Neurons ◽  
Spontaneous Frequency ◽  
Excitatory Responses ◽  
First Time

1. We report for the first time in any teleost, a quantitative in vivo study of recordings from single olfactory receptor neurons (ORNs) in the channel catfish, Ictalurus punctatus, with odorant stimuli. 2. Responses of 69 spontaneously active single ORNs were recorded simultaneously with the electroolfactogram (EOG). Recording times ranged from 10 to 72 min per receptor cell with an average of 24 +/- 15 (SD) min/cell. The averaged spontaneous frequency ranged from < 1 to 12 action potentials/s with a mean frequency of 4.7 +/- 2.5 action potentials/s. 3. Catfish ORNs responded to the odorant stimuli (amino acids, bile salts, and ATP) with either an excitation or suppression of the background neural activity. Suppressive responses were encountered more frequently than excitatory responses, suggesting that suppressive responses also play an important role in olfactory coding. 4. Excitatory and suppressive responses to the different odorants were elicited from the same ORN, suggesting that different olfactory receptor molecules and different transduction pathways exist in the same ORN.

scholarly journals Odorant receptors activated by amino acids in sensory neurons of the channel catfish Ictalurus punctatus.

1993 ◽  
Vol 102 (6) ◽  
pp. 1085-1105 ◽  
Author(s):  
T T Ivanova ◽  
J Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Single Channel ◽  
Odorant Receptors ◽  
Olfactory Neurons ◽  
Whole Cell

Odorant receptors activated by amino acids were investigated with patch-clamp techniques in olfactory receptor neurons of the channel catfish, Ictalurus punctatus. The L-isomers of alanine, norvaline, arginine, and glutamate, known to act predominantly on different olfactory receptor sites, activated nondesensitizing inward currents with amplitudes of -2.5 to -280 pA in olfactory neurons voltage-clamped at membrane potentials of -72 or -82 mV. Different amino acids were shown to induce responses in the same sensory neurons; however, the amplitude and the kinetics of the observed whole cell currents differed among the stimuli and may therefore reflect activation of different amino acid receptor types or combinations of receptor types in these cells. Amino acid-induced currents appeared to have diverse voltage dependence and could also be classified according to the amplitude of the spontaneous channel fluctuations underlying the macroscopic currents. A mean single-channel conductance (gamma) of 360 fS was estimated from small noise whole-cell currents evoked by arginine within the same olfactory neuron in which a mean gamma value of 23.6 pS was estimated from 'large noise' response to norvaline. Quiescent olfactory neurons fired bursts of action potentials in response to either amino acid stimulation or application of 8-Br-cyclic GMP (100 microM), and voltage-gated channels underlying generation of action potentials were similar in these neurons. However, in whole-cell voltage-clamp, 8-Br-cyclic GMP evoked large rectangular current pulses, and single-channel conductances of 275, 220, and 110 pS were obtained from the discrete current levels. These results suggest that in addition to the cyclic nucleotide-gated transduction channels, olfactory neurons of the channel catfish possess a variety of odor receptors coupled to different types of transduction channels.

scholarly journals T-type Ca2+ channel lowers the threshold of spike generation in the newt olfactory receptor cell.

1996 ◽  
Vol 108 (6) ◽  
pp. 525-535 ◽  
Author(s):  
F Kawai ◽  
T Kurahashi ◽  
A Kaneko
Keyword(s):  
Action Potential ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Channel Blocker ◽  
Receptor Cell ◽  
Spike Generation ◽  
Current Clamp ◽  
Patch Clamp Technique ◽  
Olfactory Receptor Cell ◽  
Clamp Condition

Mechanisms underlying action potential generation in the newt olfactory receptor cell were investigated by using the whole-cell version of the patch-clamp technique. Isolated olfactory cells had a resting membrane potential of -70 +/- 9 mV. Injection of a depolarizing current step triggered action potentials under current clamp condition. The amplitude of the action potential was reduced by lowering external Na+ concentration. After a complete removal of Na+, however, cells still showed action potentials which was abolished either by Ca2+ removal or by an application of Ca2+ channel blocker (Co2+ or Ni2+), indicating an involvement of Ca2+ current in spike generation of newt olfactory receptor cells. Under the voltage clamp condition, depolarization of the cell to -40 mV from the holding voltage of -100 mV induced a fast transient inward current, which consisted of Na+ (INa) and T-type Ca2+ (ICa.T) currents. The amplitude of ICa,T was about one fourth of that of INa. Depolarization to more positive voltages also induced L-type Ca2+ current (ICa,L). ICa,L was as small as a few pA in normal Ringer solution. The activating voltage of ICa,T was approximately 10 mV more negative than that of INa. Under current clamp, action potentials generated by a least effective depolarization was almost completely blocked by 0.1 mM Ni2+ (a specific T-type Ca2+ channel blocker) even in the presence of Na+. These results suggest that ICa,T contributes to action potential in the newt olfactory receptor cell and lowers the threshold of spike generation.

Intrinsically Bursting Olfactory Receptor Neurons

2007 ◽  
Vol 97 (2) ◽  
pp. 1052-1057 ◽  
Author(s):  
Y. V. Bobkov ◽  
B. W. Ache
Keyword(s):  
Olfactory Receptor ◽  
Action Potentials ◽  
Olfactory Receptor Neurons ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Network Function ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Bursting Neurons ◽  
Receptor Neurons

Rhythmically bursting neurons are fundamental to neuronal network function but typically are not considered in the context of primary sensory signaling. We now report intrinsically bursting lobster primary olfactory receptor neurons that respond to odors with a phase-dependent burst of action potentials. Rhythmic odor input as might be generated by sniffing entrains the intrinsic bursting rhythm in a concentration-dependent manner and presumably synchronizes the ensemble of bursting cells. We suggest such intrinsically bursting olfactory receptor cells provide a novel way for encoding odor information.

Regional distribution of rat electroolfactogram

1995 ◽  
Vol 73 (6) ◽  
pp. 2207-2220 ◽  
Author(s):  
P. I. Ezeh ◽  
L. M. Davis ◽  
J. W. Scott
Keyword(s):  
Spatial Distribution ◽  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Flow Rate ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Amyl Acetate ◽  
Flow Rates ◽  
Olfactory Receptor Cells ◽  
Receptor Cells

1. Electroolfactorgram (EOG) recordings were made from different regions of the rat olfactory epithelium to test for spatial distribution of odor responses. 2. The EOG recordings showed spatial distribution of the odor responses in the olfactory epithelium. While some odorants (amyl acetate, anisole, and ethyl butyrate) were more effective in evoking responses in the dorsal recess near the septum, other odorants (including limonene, cineole, cyclooctane, and hexane) were more effective in the lateral recesses among the turbinate bones. These differences were seen as statistically significant odorant-by-position interactions in analysis of variance. 3. Comparisons of recordings along the anteroposterior dimension of the epithelium produced smaller differences between the odor responses. These were not significant for 3-mm distances, but were statistically significant for 5- to 6-mm distances along the dorsomedial epithelium. 4. The latencies were significantly longer in the lateral recesses than in the medial region. This probably reflects a more tortuous air path along the turbinate bones to the lateral recesses. 5. The olfactory receptor cells were activated by antidromic stimulation via the nerve layer of the olfactory bulb. The population spikes evoked from the olfactory receptor cells could be suppressed by prior stimulation with odorants that evoked strong EOG responses. This collision of the antidromic action potentials with the odor-evoked action potentials indicates that the same population of receptor cells was activated in both cases. 6. The flow rate and duration of the artificial sniff were varied systematically in some experiments. The differential distribution of response sizes was present at all flow rates and sniff durations. Some odors (e.g., amyl acetate and anisole) produced increased responses in the epithelium of the lateral recesses when flow rates or sniff durations were high. We suggest that these changes may reflect the sorptive properties of the nasal membranes on these odors. The responses to other odors (e.g., hexane or limonene) were not greatly affected by flow rate or sniff duration. 7. Taken with existing anatomic data, the results indicate that the primary olfactory neurons that project axons to glomeruli in different parts of the olfactory bulb are responsive to different odors. The latency differences between responses at medial and lateral sites are large enough to be physiologically significant in the generation of the patterned responses of olfactory bulb neurons.

Whole cell recording from lobster olfactory receptor cells: responses to current and odor stimulation

1989 ◽  
Vol 61 (5) ◽  
pp. 994-1000 ◽  
Author(s):  
I. Schmiedel-Jakob ◽  
P. A. Anderson ◽  
B. W. Ache
Keyword(s):  
Membrane Potential ◽  
Electrical Properties ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Receptor Potential ◽  
Membrane Potentials ◽  
Patch Clamp Recording ◽  
Whole Cell ◽  
Olfactory Receptor Cells ◽  
Receptor Cells

1. The basic electrical properties of olfactory (antennule) receptor cells were studied in an in situ preparation of the spiny lobster using whole cell patch-clamp recording. 2. The current-voltage relationship of the cells was linear for membrane potentials between -150 and -40 mV and rectified at more positive membrane potentials. The input resistance at rest averaged 508 M omega. The cells displayed two time constants, with mean values of 29.8 and 8.2 ms. 3. Depolarizing current steps elicited fast, overshooting action potentials at a mean threshold of -32 mV from an imposed resting membrane potential of -65 mV. The action potentials were tetrodotoxin (TTX) and tetraethylammonium (TEA) sensitive, suggesting they are typical sodium/potassium action potentials. 4. Odor stimulation evoked slow, dose-dependent, depolarizing receptor potentials up to 50 mV in amplitude. In approximately 30% of cells tested, these led to repetitive spiking when the cells were depolarized beyond -45 to -30 mV. The amplitude of the receptor potential was graded as a linear function of the logarithm of the odor concentration. 5. The amplitude of the receptor potential varied linearly with the membrane potential between -70 and -30 mV. Extrapolated reversal potentials appeared to be normally distributed around a mean value of -3.6 mV. 6. The results collectively indicate that lobster olfactory receptor cells have electrical properties similar to, but not necessarily identical with, those currently envisaged for olfactory receptor cells in other species.

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