Response properties of isolated mouse olfactory receptor cells

Abstract

Response properties of isolated mouse olfactory receptor cells were investigated using the suction pipette technique. Cells were exposed to the odour cineole or to solutions of modified ionic content by rapidly changing the solution superfusing the cilia. All experiments were performed at 37°C. Mouse olfactory receptor cells displayed a steep dependence of action potential frequency on stimulus concentration, a 3‐fold increase in stimulus concentration often saturating the firing frequency at 200‐300 Hz. The receptor current increased more gradually with increasing cineole concentration and did not saturate within the 100‐fold range of cineole concentrations applied. When stimulated for 30 s with a low odour concentration, cells responded with sporadic spike firing. Higher concentrations led to the generation of a large receptor current at the onset of stimulation which returned to baseline levels within a few seconds, accompanied during its rising phase by a short burst of action potentials. Thereafter an oscillating response pattern was observed during the remainder of the stimulus, consisting of repetitive increases in receptor current of around 1 s duration accompanied by short bursts of action potentials. Olfactory adaptation was studied by comparing the responses to two closely spaced odour stimuli. The response to the second odour stimulus recovered to 80% of its original magnitude when the cell was superfused with Ringer solution during the 5 s interval between odour exposures. In contrast, exposure to a choline‐substituted low Na+ solution between odour stimuli had two effects. First, the receptor current response to the first odour stimulus did not terminate as quickly as in the presence of Na+, suggesting the presence of a Na+‐Ca2+ exchanger. Second, the response to the second stimulus only recovered to 55% of its original magnitude, demonstrating the involvement of Na+‐Ca2+ exchange in the recovery of sensitivity in mouse olfactory receptor cells following stimulation.

Fold-change detection and scalar symmetry of sensory input fields

“…Examples include sensory modalities such as auditory searches for sound sources and olfactory searches for odorant sources (47)(48)(49)(50). Experiments can investigate this on several levels: whether search movement is independent of signal source strength, whether the input-output relationship shows FCD, and whether the molecular mechanism follows the present conditions for FCD.…”

Impaired Channel Targeting and Retinal Degeneration in Mice Lacking the Cyclic Nucleotide-Gated Channel Subunit CNGB1

“…The tissue was transferred to the recording chamber and perfused with bicarbonatebuffered Locke's solution containing the following: 149 mM NaCl, 3.6 mM KCl, 2.4 mM MgCl 2 , 1.2 mM CaCl 2 , 10 mM HEPES, pH 7.4, 0.02 mM EDTA, 3 mM NaHCO 3 , 3 mM disodium succinate, 0.5 mM sodium glutamate, 0.1% vitamins and amino-acid supplement (Invitrogen, San Diego, CA), and 10 mM glucose, bubbled with 95% O 2 -5% CO 2 . The perfusion solution was heated to 37-38°C (Reisert and Matthews, 2001), and the temperature of the solution in the chamber was monitored continuously with a telethermometer. An individual rod outer segment (ROS) projecting from a piece of retina was drawn into a suction electrode containing the following (in mM): 140 NaCl, 3.6 KCl, 2.4 MgCl 2 , 1.2 CaCl 2 , 3 HEPES, pH 7.4, 0.02 EDTA, and 10 glucose.…”

Computational model of the cAMP-mediated sensory response and calcium-dependent adaptation in vertebrate olfactory receptor neurons

“…Longer-lasting adaptation effects with recovery time constants of minutes also have been reported (7). In addition, oscillations in the receptor current have been observed when ORNs are exposed to prolonged stimulation (16,17).…”

“…Longer-lasting adaptation effects with recovery time constants of minutes also have been reported (7). In addition, oscillations in the receptor current have been observed when ORNs are exposed to prolonged stimulation (16,17).It is not yet clear to what extent each of these mechanisms contributes to the shaping of odor responses and modulation of cell sensitivity across different timescales. Mathematical modeling of olfactory transduction can help to elucidate how these various cellular processes participate in the coding of odor stimuli.…”