Sensory Transduction in Photoreceptors and Olfactory Sensory Neurons: Common Features and Distinct Characteristics

Genovese, Federica; Reisert, Johannes; Kefalov, Vladimir J.

doi:10.3389/fncel.2021.761416

Cited by 15 publications

(15 citation statements)

References 136 publications

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“…Melanopsin (OPN4) is more ancient in terms of evolution than rod/cone opsins (Provencio et al, 2000) and engages different phototransduction cascades, resulting in cellular depolarization (for review, see Peirson and Foster, 2006). Thus, ipRGCs are very unusual photoreceptors; they are spiking neurons that depolarize in response to light, unlike rods and cones that are highly specialized neurons that respond to light with graded hyperpolarization (for review, see Genovese et al, 2021). Unlike rods and cones, which signal to the brain via second-and third-order retinal neurons, ipRGCs communicate light information to the brain directly, i.e.…”

Section: Iprgcs' Non-visual Pathwaymentioning

confidence: 99%

The Newborn's Reaction to Light as the Determinant of the Brain's Activation at Human Birth

Polese

Riccio

Fagioli

et al. 2022

Front. Integr. Neurosci.

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Developmental neuroscience research has not yet fully unveiled the dynamics involved in human birth. The trigger of the first breath, often assumed to be the marker of human life, has not been characterized nor has the process entailing brain modification and activation at birth been clarified yet. To date, few researchers only have investigated the impact of the extrauterine environment, with its strong stimuli, on birth. This ‘hypothesis and theory' article assumes the role of a specific stimulus activating the central nervous system (CNS) at human birth. This stimulus must have specific features though, such as novelty, efficacy, ubiquity, and immediacy. We propose light as a robust candidate for the CNS activation via the retina. Available data on fetal and neonatal neurodevelopment, in particular with reference to retinal light-responsive pathways, will be examined together with the GABA functional switch, and the subplate disappearance, which, at an experimental level, differentiate the neonatal brain from the fetal brain. In this study, we assume how a very rapid activation of retinal photoreceptors at birth initiates a sudden brain shift from the prenatal pattern of functions to the neonatal setup. Our assumption implies the presence of a photoreceptor capable of capturing and transducing light/photon stimulus, transforming it into an effective signal for the activation of new brain functions at birth. Opsin photoreception or, more specifically, melanopsin-dependent photoreception, which is provided by intrinsically photosensitive retinal ganglion cells (ipRGCs), is considered as a valid candidate. Although what is assumed herein cannot be verified in humans based on knowledge available so far, proposing an important and novel function can trigger a broad range of diversified research in different domains, from neurophysiology to neurology and psychiatry.

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Section: Iprgcs' Non-visual Pathwaymentioning

confidence: 99%

The Newborn's Reaction to Light as the Determinant of the Brain's Activation at Human Birth

Polese

Riccio

Fagioli

et al. 2022

Front. Integr. Neurosci.

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“…1B ). They are involved in the generation and regulation of the photoreceptor’s electrical response to light (48). The functional CNG channel in rods is a constitutive tetramer containing three CNGα1 and one CNGβ1 subunits.…”

Section: Discussionmentioning

confidence: 99%

Absolute quantification of photoreceptor outer segment proteins

Skiba

Lewis

Spencer

et al. 2023

Preprint

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Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously measure the outer segment content of twenty key structural and functional proteins. We determined the molar ratio amongst all twenty proteins as well as the number of molecules of each protein residing within an outer segment. To assess the precision of this quantification, we took advantage of the fact that seven of these proteins exist within three constitutive complexes of well-established subunit stoichiometries. Remarkably, our measurements differed from these stoichiometries by less than 7%, highlighting the exceptional precision of our quantification. This allowed us to resolve the existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.

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“…ONs are described as sharing “an amazing level of similarity” to photoreceptors in several aspects. In addition, the OR complexity compared to photoreceptors is evidenced by the use of five opsin genes to cover the visible spectrum, whereas ONs use hundreds of OR genes to cover the odor space [ 55 ]. The isolation of genes that code for olfactory receptors which showed they belonged to the class of Gprotein-coupled receptors led to the award of the 2004 Nobel Prize in Physiology or Medicine [ 56 ], exemplifying the importance of olfaction research in the scientific community.…”

Section: Activation Of Ors By Photonsmentioning

confidence: 99%

The Luminescence Hypothesis of Olfaction

Willeford

2023

Sensors

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A new hypothesis for the mechanism of olfaction is presented. It begins with an odorant molecule binding to an olfactory receptor. This is followed by the quantum biology event of inelastic electron tunneling as has been suggested with both the vibration and swipe card theories. It is novel in that it is not concerned with the possible effects of the tunneled electrons as has been discussed with the previous theories. Instead, the high energy state of the odorant molecule in the receptor following inelastic electron tunneling is considered. The hypothesis is that, as the high energy state decays, there is fluorescence luminescence with radiative emission of multiple photons. These photons pass through the supporting sustentacular cells and activate a set of olfactory neurons in near-simultaneous timing, which provides the temporal basis for the brain to interpret the required complex combinatorial coding as an odor. The Luminescence Hypothesis of Olfaction is the first to present the necessity of or mechanism for a 1:3 correspondence of odorant molecule to olfactory nerve activations. The mechanism provides for a consistent and reproducible time-based activation of sets of olfactory nerves correlated to an odor.The hypothesis has a biological precedent: an energy feasibility assessment is included, explaining the anosmia seen with COVID-19, and can be confirmed with existing laboratory techniques.

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Sensory Transduction in Photoreceptors and Olfactory Sensory Neurons: Common Features and Distinct Characteristics

Cited by 15 publications

References 136 publications

The Newborn's Reaction to Light as the Determinant of the Brain's Activation at Human Birth

The Newborn's Reaction to Light as the Determinant of the Brain's Activation at Human Birth

Absolute quantification of photoreceptor outer segment proteins

The Luminescence Hypothesis of Olfaction

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