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.

Receptor Potentials and Electrical Properties of Nonspiking Stretch-Receptive Neurons in the Sand Crab Emerita analoga (Anomura, Hippidae)

1999 ◽  
Vol 81 (5) ◽  
pp. 2493-2500 ◽  
Author(s):  
Dorothy H. Paul ◽  
Jan Bruner
Keyword(s):  
Membrane Potential ◽  
Electrical Properties ◽  
Full Range ◽  
Receptor Potential ◽  
Membrane Potentials ◽  
Elastic Recoil ◽  
Intact Cells ◽  
Electrode Current ◽  
Current Pulses ◽  
Emerita Analoga

Receptor potentials and electrical properties of nonspiking stretch-receptive neurons in the sand crab Emerita analoga (Anomura, Hippidae). Four nonspiking, monopolar neurons with central somata and large peripheral dendrites constitute the sole innervation of the telson-uropod elastic strand stretch receptor in Emerita analoga. We characterized their responses to stretch and current injection, using two-electrode current clamp, in intact cells and in two types of isolated peripheral dendritic segments, one that included and one that excluded the dendritic termini (mechanosensory membrane). The membrane potentials of intact cells at rest (mean ± SD: −57 ± 4.4 mV, n = 30), recorded in peripheral or neuropil processes, are similar to the membrane potentials of isolated dendritic segments and always less negative than membrane potentials of motoneurons and interneurons recorded in the same preparations. Ion substitution experiments indicate that the membrane potential is influenced strongly by Na+ conductance, probably localized in the mechanotransducing terminals within the elastic strand. The form of the receptor potential in response to ramp-hold-release stretch remains the same as stretch amplitude is varied and is not dependent on initial membrane potential (−70 to −30 mV) or recording site: initial depolarization (slope follows ramp of applied stretch), terminated by rapid, partial repolarization to a plateau (delayed depolarization) that is intermediate between the peak depolarization and the initial potential and sustained for the duration of the stretch. Responses to depolarizing current pulses are similar to stretch-evoked receptor potentials, except for small amplitude stimuli: an initial peak occurs only in response to stretch and probably reflects elastic recoil of the extracellular matrix surrounding the dendritic terminals. The rapid, partial repolarization depends on holding potential and is abolished by 4-aminopyridine (4-AP; 10 mM), implicating a fast-activating, fast-inactivating K+ conductance; TEA (60 mM) abolishes the remaining slow repolarization to the plateau. In intact cells, but not dendritic segments, regenerative depolarizations can arise in response to stretch or depolarizing current pulses; they are reduced by CdCl2 (10 μM) in the saline containing TEA and 4-AP and probably reflect current spread from Ca2+ influx at presynaptic terminals in the ganglion. We found no evidence for other voltage-activated conductances. Unlike morphologically similar “nonspiking” thoracic receptors of other species, E. analoga’s nonspiking neurons are electrically compact and do not boost the analogue afferent signal by voltage-activated inward currents. The most prominent (only?) voltage-activated extra-ganglionic conductances are for potassium; by reducing the slope of the stretch-plateau depolarization curve, they extend each neuron’s functional range to the full range of sensitivity of the receptor.

Acetylcholine enhances excitability by lowering the threshold of spike generation in olfactory receptor cells

2013 ◽  
Vol 110 (9) ◽  
pp. 2082-2089 ◽  
Author(s):  
Mahito Ohkuma ◽  
Fusao Kawai ◽  
Ei-ichi Miyachi
Keyword(s):  
Muscarinic Receptor ◽  
Olfactory Receptor ◽  
Calcium Current ◽  
Sodium Current ◽  
Delayed Rectifier ◽  
Patch Clamp Recording ◽  
Spike Generation ◽  
Voltage Gated ◽  
Olfactory Receptor Cells ◽  
Receptor Cells

Olfactory perception is influenced by behavioral states, presumably via efferent regulation. Using the whole cell version of patch-clamp recording technique, we discovered that acetylcholine, which is released from efferent fibers in the olfactory mucosa, can directly affect the signal encoding in newt olfactory receptor cells (ORCs). Under current-clamp conditions, application of carbachol, an acetylcholine receptor agonist, increased the spike frequency of ORCs and lowered their spike threshold. When a 3-pA current to induce near-threshold depolarization was injected into ORCs, 0.0 spikes/s were generated in control solution and 0.5 spikes/s in the presence of carbachol. By strong stimuli of injection of a 13-pA current into ORCs, 9.1 and 11.0 spikes/s were generated in control and carbachol solutions, respectively. A similar result was observed by bath application of 50 μM acetylcholine. Under voltage-clamp conditions, carbachol increased the peak amplitude of a voltage-gated sodium current by 32% and T-type calcium current by 39%. Atropine, the specific muscarinic receptor antagonist, blocked the enhancement by carbachol of the voltage-gated sodium current and T-type calcium current, suggesting that carbachol increases those currents via the muscarinic receptor rather than via the nicotinic receptor. In contrast, carbachol did not significantly change the amplitude of the L-type calcium current or the delayed rectifier potassium current in the ORCs. Because T-type calcium current is known to lower the threshold in ORCs, we suggest that acetylcholine enhance excitability by lowering the threshold of spike generation in ORCs via the muscarinic receptor.

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.

scholarly journals Transduction Mechanisms in Vertebrate Olfactory Receptor Cells

1998 ◽  
Vol 78 (2) ◽  
pp. 429-466 ◽  
Author(s):  
DETLEV SCHILD ◽  
DIEGO RESTREPO
Keyword(s):  
G Protein ◽  
Olfactory Receptor ◽  
Reversal Potential ◽  
Receptor Potential ◽  
Second Messenger ◽  
Cation Channels ◽  
Inositol Polyphosphate ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Transduction Mechanisms

Schild, Detlev, and Diego Restrepo. Transduction Mechanisms in Vertebrate Olfactory Receptor Cells. Physiol. Rev. 78: 429–466, 1998. — Considerable progress has been made in the understanding of transduction mechanisms in olfactory receptor neurons (ORNs) over the last decade. Odorants pass through a mucus interface before binding to odorant receptors (ORs). The molecular structure of many ORs is now known. They belong to the large class of G protein-coupled receptors with seven transmembrane domains. Binding of an odorant to an OR triggers the activation of second messenger cascades. One second messenger pathway in particular has been extensively studied; the receptor activates, via the G protein Golf , an adenylyl cyclase, resulting in an increase in adenosine 3′,5′-cyclic monophosphate (cAMP), which elicits opening of cation channels directly gated by cAMP. Under physiological conditions, Ca2+ has the highest permeability through this channel, and the increase in intracellular Ca2+ concentration activates a Cl− current which, owing to an elevated reversal potential for Cl−, depolarizes the olfactory neuron. The receptor potential finally leads to the generation of action potentials conveying the chemosensory information to the olfactory bulb. Although much less studied, other transduction pathways appear to exist, some of which seem to involve the odorant-induced formation of inositol polyphosphates as well as Ca2+ and/or inositol polyphosphate-activated cation channels. In addition, there is evidence for odorant-modulated K+ and Cl− conductances. Finally, in some species, ORNs can be inhibited by certain odorants. This paper presents a comprehensive review of the biophysical and electrophysiological evidence regarding the transduction processes as well as subsequent signal processing and spike generation in ORNs.

scholarly journals Electrical responses to Chemical Stimulation of Squid Olfactory Receptor Cells

1992 ◽  
Vol 162 (1) ◽  
pp. 231-249 ◽  
Author(s):  
MARY T. LUCERO ◽  
FRANK T. HORRIGAN ◽  
WM F. GILLY
Keyword(s):  
Olfactory Receptor ◽  
Action Potentials ◽  
Membrane Conductance ◽  
Ammonium Ions ◽  
Behavioral Experiments ◽  
K Channels ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Whole Cell Patch Clamp ◽  
Quaternary Ammonium Ions

Electrical properties of isolated olfactory receptor cells were studied usingb voltage- and current-clamp techniques based on whole-cell patch-clamp methods. Squid olfactory receptor cells contain voltage-gated Na+ and K+ channels and are capable of generating action potentials. Chemicals that elicit escape-jetting responses in behavioral experiments affect the excitability of isolated receptor cells. One set of such chemicals, including quaternary ammonium ions and aminopyridines, blocks K+ channels and increases excitability. Squid ink and L-Dopa also elicit escape jetting, but these substances increase membrane conductance, hyperpolarize the receptor cell and decrease excitability. These experiments indicate that sensory neurons of the olfactory organ are capable of detecting chemical signals and that at least two different transduction mechanismscan lead to similar behavioral responses.

Ultrastructural aspects of olfactory signal transduction and its development

1994 ◽  
Vol 52 ◽  
pp. 142-143
Author(s):  
Bert Ph. M. Menco
Keyword(s):  
Signal Transduction ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Freeze Substitution ◽  
Luminal Surface ◽  
Tissue Sections ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Olfactory Signal ◽  
Odor Molecule

Vertebrate olfactory receptor cells are specialized neurons that have numerous long tapering cilia. The distal parts of these cilia line the interface between the external odorous environment and the luminal surface of the olfactory epithelium. The length and number of these cilia results in a large surface area that presumably increases the chance that an odor molecule will meet a receptor cell. Advanced methods of cryoprepration and immuno-gold labeling were particularly useful to preserve the delicate ultrastructural and immunocytochemical features of olfactory cilia required for localization of molecules involved in olfactory signal-transduction. We subjected olfactory tissues to freeze-substitution in acetone (unfixed tissues) or methanol (fixed tissues) followed by low temperature embedding in Lowicryl K11M for that purpose. Tissue sections were immunoreacted with several antibodies against proteins that are presumably important in olfactory signal-transduction.

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