Distinct axonal projections from two types of olfactory receptor neurons in the middle chamber epithelium of Xenopus laevis

2011 ◽  
Vol 346 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Shoko Nakamuta ◽  
Nobuaki Nakamuta ◽  
Kazuyuki Taniguchi
Keyword(s):  
Xenopus Laevis ◽  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Axonal Projections ◽  
Middle Chamber ◽  
Receptor Neurons

scholarly journals Classes and Narrowing Selectivity of Olfactory Receptor Neurons of Xenopus laevis Tadpoles

2004 ◽  
Vol 123 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Ivan Manzini ◽  
Detlev Schild
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Xenopus Laevis ◽  
Olfactory Receptor ◽  
Developmental Stages ◽  
Olfactory Receptors ◽  
Response Spectra ◽  
Olfactory Receptor Neurons ◽  
Receptor Neurons ◽  
Response Profiles

In olfactory receptor neurons (ORNs) of aquatic animals amino acids have been shown to be potent stimuli. Here we report on calcium imaging experiments in slices of the olfactory mucosa of Xenopus laevis tadpoles. We were able to determine the response profiles of 283 ORNs to 19 amino acids, where one profile comprises the responses of one ORN to 19 amino acids. 204 out of the 283 response profiles differed from each other. 36 response spectra occurred more than once, i.e., there were 36 classes of ORNs identically responding to the 19 amino acids. The number of ORNs that formed a class ranged from 2 to 13. Shape and duration of amino acid-elicited [Ca2+]i transients showed a high degree of similarity upon repeated stimulation with the same amino acid. Different amino acids, however, in some cases led to clearly distinguishable calcium responses in individual ORNs. Furthermore, ORNs clearly appeared to gain selectivity over time, i.e., ORNs of later developmental stages responded to less amino acids than ORNs of earlier stages. We discuss the narrowing of ORN selectivity over stages in the context of expression of olfactory receptors.

scholarly journals Ca2+-activated Cl current predominates in threshold response of mouse olfactory receptor neurons

2018 ◽  
Vol 115 (21) ◽  
pp. 5570-5575 ◽  
Author(s):  
Rong-Chang Li ◽  
Chih-Chun Lin ◽  
Xiaozhi Ren ◽  
Jingjing Sherry Wu ◽  
Laurie L. Molday ◽  
...  
Keyword(s):  
Olfactory Receptor ◽  
Signal Amplification ◽  
Olfactory Receptor Neurons ◽  
Behavioral Threshold ◽  
Olfactory Transduction ◽  
Threshold Response ◽  
Axonal Projections ◽  
Cl Channels ◽  
Receptor Neurons ◽  
The Brain

In mammalian olfactory transduction, odorants activate a cAMP-mediated signaling pathway that leads to the opening of cyclic nucleotide-gated (CNG), nonselective cation channels and depolarization. The Ca2+ influx through open CNG channels triggers an inward current through Ca2+-activated Cl channels (ANO2), which is expected to produce signal amplification. However, a study on an Ano2−/− mouse line reported no elevation in the behavioral threshold of odorant detection compared with wild type (WT). Subsequent studies by others on the same Ano2−/− line, nonetheless, found subtle defects in olfactory behavior and some abnormal axonal projections from the olfactory receptor neurons (ORNs) to the olfactory bulb. As such, the question regarding signal amplification by the Cl current in WT mouse remains unsettled. Recently, with suction-pipette recording, we have successfully separated in frog ORNs the CNG and Cl currents during olfactory transduction and found the Cl current to predominate in the response down to the threshold of action-potential signaling to the brain. For better comparison with the mouse data by others, we have now carried out similar current-separation experiments on mouse ORNs. We found that the Cl current clearly also predominated in the mouse olfactory response at signaling threshold, accounting for ∼80% of the response. In the absence of the Cl current, we expect the threshold stimulus to increase by approximately sevenfold.

Inhibitory and excitatory responses of olfactory receptor neurons of xenopus laevis tadpoles to stimulation with amino acids

1999 ◽  
Vol 202 (8) ◽  
pp. 997-1003 ◽  
Author(s):  
C. Vogler ◽  
D. Schild
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Xenopus Laevis ◽  
Olfactory Receptor ◽  
Olfactory Receptor Neurons ◽  
Patch Clamp Technique ◽  
Olfactory Neurons ◽  
Receptor Neurons ◽  
Patch Configuration ◽  
Excitatory Responses

Recordings were made from olfactory receptor neurons of Xenopus laevis tadpoles using the patch-clamp technique to investigate the responses of these cells to odorants. Four amino acids (glutamate, methionine, arginine and alanine) both individually and as a mixture were used as stimuli. Of the 156 olfactory neurons tested, 43 showed a response to at least one of the stimuli. Of the cells tested, 19 % responded to glutamate, 16 % to methionine, 12 % to arginine and 10 % to alanine. Each amino acid was able to induce both excitatory and inhibitory responses, although these occurred in different cells. Each amino acid produced approximately equal numbers of inhibitory and excitatory responses. Inhibitory responses could best be observed in the perforated-patch configuration using gramicidin as an ionophore and a recording configuration that is a current-clamp for fast signals and a voltage-clamp for slow signals. The diversity of the odorant responses, in particular the existence of excitatory and inhibitory responses, is not consistent with a single transduction pathway in olfactory neurons of Xenopus laevis tadpoles.

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