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.

Presynaptic Afferent Inhibition of Lobster Olfactory Receptor Cells: Reduced Action-Potential Propagation Into Axon Terminals

1998 ◽  
Vol 80 (2) ◽  
pp. 1011-1015 ◽  
Author(s):  
Matt Wachowiak ◽  
Lawrence B. Cohen
Keyword(s):  
Action Potential ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Action Potential Propagation ◽  
Cell Axon ◽  
Axon Terminals ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Afferent Inhibition ◽  
Reduced Action

Wachowiak, Matt and Lawrence B. Cohen. Presynaptic afferent inhibition of lobster olfactory receptor cells: reduced action-potential propagation into axon terminals. J. Neurophysiol. 80: 1011–1015, 1998. Action-potential propagation into the axon terminals of olfactory receptor cells was measured with the use of voltage-sensitive dye imaging in the isolated spiny lobster brain. Conditioning shocks to the olfactory nerve, known to cause long-lasting suppression of olfactory lobe neurons, allowed the selective imaging of activity in receptor cell axon terminals. In normal saline the optical signal from axon terminals evoked by a test stimulus was brief (40 ms) and small in amplitude. In the presence of low-Ca2+/high-Mg2+ saline designed to reduce synaptic transmission, the test response was unchanged in time course but increased significantly in amplitude (57 ± 16%, means ± SE). This increase suggests that propagation into receptor cell axon terminals is normally suppressed after a conditioning shock; this suppression is presumably synaptically mediated. Thus our results show that presynaptic inhibition occurs at the first synapse in the olfactory pathway and that the inhibition is mediated, at least in part, via suppression of action-potential propagation into the presynaptic terminal.

Inhibition of lobster olfactory receptor cells by an odor-activated potassium conductance

1991 ◽  
Vol 65 (3) ◽  
pp. 446-453 ◽  
Author(s):  
W. C. Michel ◽  
T. S. McClintock ◽  
B. W. Ache
Keyword(s):  
Olfactory Receptor ◽  
Receptor Cell ◽  
Odorant Receptor ◽  
Potassium Conductance ◽  
Reversal Potential ◽  
Chloride Conductance ◽  
Equilibrium Potential ◽  
Current Clamp ◽  
Olfactory Receptor Cells ◽  
Receptor Cells

1. Whole cell current-clamp recordings show that odors not only depolarize but may also hyperpolarize lobster olfactory receptor cells. Odor-evoked hyperpolarizations occurred in 36% of 178 receptor cells examined. Cell-attached recordings of action potentials followed by current-clamp recordings in the same cell indicate that depolarizing and hyperpolarizing responses were associated with increases (excitation) and decreases (inhibition) in action potential frequency, respectively. Since odorants that hyperpolarized one receptor cell depolarized other cells and since individual cells may be both excited and inhibited, the inhibitory and excitatory nature of the response must be conferred by the odorant-receptor and transduction processes expressed by the receptor cell. 2. The input resistance dropped from 1.73 G omega at rest to 1.45 G omega during odor-evoked hyperpolarization, and the membrane time constant correspondingly decreased from 114 to 61 ms. The increased conductance persisted throughout the stimulation period (5 s). 3. Shifting the K+ reversal to a more negative potential by lowering the [K+]o from 14 to 2.8 mM increased the magnitude of hyperpolarization. The hyperpolarization could be reversibly blocked by dendritic treatment with 5-10 mM 4-aminopyridine (4-AP) or 10 mM cesium ion, but not by 10 mM tetraethylammonium (TEA). 4. Substituting 80% of the [Cl-]o with NO3- increased the amplitude of the hyperpolarization. Based on a calculated equilibrium potential of -32 mV for chloride, an increase in chloride conductance in a low [Cl-]o environment should have decreased the magnitude of the response. Presumably the change in [Cl-]o acts through the dendritic steady-state chloride conductance to shift the membrane potential further from the reversal potential for K+.(ABSTRACT TRUNCATED AT 250 WORDS)

Histamine-induced modulation of olfactory receptor neurones in two species of lobster, Panulirus argus and Homarus americanus

1989 ◽  
Vol 145 (1) ◽  
pp. 133-146 ◽  
Author(s):  
T. A. Bayer ◽  
T. S. McClintock ◽  
U. Grunert ◽  
B. W. Ache
Keyword(s):  
Receptor Antagonist ◽  
Olfactory Receptor ◽  
Single Cells ◽  
Homarus Americanus ◽  
Chloride Ions ◽  
Electrophysiological Recording ◽  
Stimulus Response ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
The One

In two species of lobster, application of the biogenic amine, histamine (HA), to the soma of olfactory receptor cells suppressed both spontaneous and odour-evoked activity, as shown by electrophysiological recording from single cells. The action of HA was graded, reversible, specific to HA, and had a threshold between 0.1 and 1 mumol l-1. HA increased the conductance of the membrane, primarily to chloride ions. The vertebrate HA receptor antagonist, cimetidine, and the nicotinic receptor antagonist, d-tubocurarine, but not other known vertebrate HA receptor antagonists, reversibly blocked the action of HA. These results suggest that a histaminergic mechanism modulates stimulus-response coupling in lobster olfactory receptor cells and potentially implicate a novel HA receptor, pharmacologically similar to the one recently described in the visual system of flies.

Disorders of the Cranial Nerves and Brainstem

2021 ◽  
pp. 851-861
Author(s):  
Kelly D. Flemming
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Receptor ◽  
Cranial Nerves ◽  
Olfactory Nerve ◽  
Mitral Cell ◽  
Olfactory Cortex ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Clinical Disorders ◽  
Primary Olfactory Cortex

This chapter briefly repeats key anatomic characteristics and then reviews clinical disorders affecting each cranial nerve in addition to the brainstem. More specifically, this chapter covers cranial nerves I, V, VII, and IX through XII plus the brainstem. The olfactory nerve is a special visceral afferent nerve that functions in the sense of smell. The axons of the olfactory receptor cells within the nasal cavity extend through the cribriform plate to the olfactory bulb. These olfactory receptor cell axons synapse with mitral cells in the olfactory bulb. Mitral cell axons project to the primary olfactory cortex and amygdala. The olfactory cortex interconnects with various autonomic and visceral centers.

Responses of olfactory receptor cells of spiny lobsters to binary mixtures. II. Pattern mixture interactions

1991 ◽  
Vol 66 (1) ◽  
pp. 131-139 ◽  
Author(s):  
C. D. Derby ◽  
M. N. Girardot ◽  
P. C. Daniel
Keyword(s):  
Binary Mixtures ◽  
Olfactory Receptor ◽  
Neural Coding ◽  
Spiny Lobster ◽  
Neuronal Population ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Spiny Lobsters ◽  
Mixture Interactions

1. The effect of mixture interactions in individual olfactory receptor cells of the spiny lobster on neural coding of odorant quality of binary mixtures and their components is examined in this paper. Extracellular responses of 98 olfactory receptor cells in the antennules of spiny lobsters to seven compounds [adenosine-5'-monophosphate (AMP), betaine (Bet), L-cysteine (Cys), L-glutamate (Glu), ammonium chloride (NH4), DL-succinate (Suc), taurine (Tau)] and their binary mixtures were recorded, and mixture interactions in individual olfactory receptor cells were identified. 2. Coding of odorant quality was evaluated by examining across neuron patterns (ANPs)--the relative response magnitudes across neuronal populations. ANPs are a feature of the neuronal population response and are a possible concentration-independent code of odorant quality in this system, as indicated by previous studies and present results. 3. For most binary mixtures the diversity of types and degrees of mixture interactions across the individual cells of a population of cells resulted in ANPs for each mixture to be different from the ANPs for the components of the mixture and different from the ANP predicted for the mixture from the responses to the components (Figs. 2–10). These effects are called pattern mixture interactions (PMIs). PMIs occurred for most binary mixtures, even those that did not produce statistically significant intensity mixture interactions (IMIs) for this same population of cells. 4. The results suggest that PMIs can influence coding of stimulus quality, in some cases by causing an improvement of the contrast between the quality of mixtures and some of their components.

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