Photic Sneeze Reflex: Another Variant of the Trigeminocardiac Reflex?

Chowdhury, Tumul; Sternberg, Zohara; Golanov, Eugene V.; Gelpi, Riccardo; Rosemann, Thomas; Schaller, Bernhard

doi:10.2217/fnl-2019-0007

Cited by 4 publications

(1 citation statement)

References 89 publications

(144 reference statements)

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“…Although the detailed molecular mechanisms responsible for the photic sneeze reflex have not yet been investigated [ 47 ], it is possible that dysfunction of ciliary beating is induced by photoirradiation, as in sea urchin systems, and causes the sneezing reflex in the absence of any debris or irritants. In particular, ciliary beating in the nose/nasal cavity is controlled by cholinergic neurons, and it has been suggested that dysfunction of these neurons is the reason for the photic sneeze reflex [ 48 ]. It is of interest if the cessation of cholinergic neuron signaling and the consequent sneeze reflex are induced by photoirradiation, since our data might provide hints to help determine whether the light-induced response of cilia is present in vertebrates and whether the involved system is conserved between echinoderms and vertebrates.…”

Section: Discussionmentioning

confidence: 99%

Planktonic sea urchin larvae change their swimming direction in response to strong photoirradiation

et al. 2022

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To survive, organisms need to precisely respond to various environmental factors, such as light and gravity. Among these, light is so important for most life on Earth that light-response systems have become extraordinarily developed during evolution, especially in multicellular animals. A combination of photoreceptors, nervous system components, and effectors allows these animals to respond to light stimuli. In most macroscopic animals, muscles function as effectors responding to light, and in some microscopic aquatic animals, cilia play a role. It is likely that the cilia-based response was the first to develop and that it has been substituted by the muscle-based response along with increases in body size. However, although the function of muscle appears prominent, it is poorly understood whether ciliary responses to light are present and/or functional, especially in deuterostomes, because it is possible that these responses are too subtle to be observed, unlike muscle responses. Here, we show that planktonic sea urchin larvae reverse their swimming direction due to the inhibitory effect of light on the cholinergic neuron signaling>forward swimming pathway. We found that strong photoirradiation of larvae that stay on the surface of seawater immediately drives the larvae away from the surface due to backward swimming. When Opsin2, which is expressed in mesenchymal cells in larval arms, is knocked down, the larvae do not show backward swimming under photoirradiation. Although Opsin2-expressing cells are not neuronal cells, immunohistochemical analysis revealed that they directly attach to cholinergic neurons, which are thought to regulate forward swimming. These data indicate that light, through Opsin2, inhibits the activity of cholinergic signaling, which normally promotes larval forward swimming, and that the light-dependent ciliary response is present in deuterostomes. These findings shed light on how light-responsive tissues/organelles have been conserved and diversified during evolution.

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Section: Discussionmentioning

confidence: 99%

Planktonic sea urchin larvae change their swimming direction in response to strong photoirradiation

et al. 2022

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Biophysical parameters affecting lung surfactant function, surface tension and the transition from aerosol to droplet exhalation (in relation to COVID-19 infection)

Allaerts

2021

J. Phys.: Conf. Ser.

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A considerable number of biophysical and biochemical studies has increased our understanding of the surface activity of surfactant proteins B and C (SP-B, SP-C) in the (mammalian) lung and their importance for a healthy, proper breathing system. For instance, it is well-known that these surfactant proteins are released from the lamellar bodies of type II cells of the lung alveoli (type II pneumocytes), and that at compression, the lipid-protein monolayer of the surfactant is squeezed into three-dimensional (3D) stacks, acting as a surfactant reservoir. Moreover, studies have demonstrated the influence of hydrophobic nanoparticles on lung surfactant model systems, well before the outbreak of the COVID-19 pandemic. The potentially devastating effect of SARS-CoV-2 infection on vital lung function, including pneumonia and Acute respiratory distress syndrome (ARDS), meanwhile has been confirmed worldwide by thousands of fatal cases, although the mechanism of its onset is not completely understood. In theory, any virus carrying palmitoylated spike proteins (like beta-coronaviruses in general) might interfere with the alveolar surface activity, when infecting the deep respiratory system. However, it is clearly established that SARS-CoV-2 uses the Angiotensin converting enzyme 2 receptor (ACE2) for entry in the host, which receptor is expressed on the same type II pneumocytes, and, as a result, the virus may directly interfere with the secretion of surfactant proteins. This study aims at elucidating the main targets for containment of the spread of the SARS-CoV-2 virus via the respiratory system, a better understanding of the role of virus-surfactant interactions, the formation of aerosols and role of the inflammatory components of the immune system, as well as the role of positive pressure ventilation systems on particle exhalation, as being used at ICUs. Finally, suggestions are made for important goals for future biophysics research in infectious disease prevention and containment.

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Sneezing in response to bright light exposure: A case study in a photic sneezer

Bickerstaff,

Trinkl,

Munkwitz

et al. 2024

Preprint

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Background: The photic sneeze reflex (PSR) is a widespread, yet understudied phenomenon characterised by sneezing in response to bright-light exposure, reportedly affecting around 30% of the general population. Our goals were to collect real-world data to characterise PSR-inducing naturalistic light conditions, and to develop an indoor protocol to reliably induce the PSR in affected subjects using parametric stimuli. Methods: This study was carried out on one male adult affected by photic sneezing (n=1). To characterise naturalistic light conditions eliciting photic sneezing, real-world light exposure was measured over a 30-day period, while logging PSR events. To study photic sneezing in response to artificial stimuli, a setup including a multi-primary LED source and an integrating sphere was used to present 30-second light stimuli to the subject while collecting pupillometric data with an eye-tracker. Results: 82 photic sneeze events were recorded, with an average of 2.73 sneezes per day and a range of 1 to 6 sneezes per event. At a sneeze event, illuminance is on average ten times bigger than five minutes before the sneeze event. A significant increase in illuminance is observed around 2 minutes before the sneeze event. Light levels go back down to pre-sneeze levels within 10 minutes after sneezing. Despite exposure to more than 150 stimuli, no sneeze could be artificially induced in the subject. However, a strong tickling sensation was consistently reported, especially for high illuminance settings. Conclusions: Real-world light data confirmed that a sudden increase in environmental lighting conditions can induce photic sneezing. Further analysis could be relevant on instances of illuminance increments not eliciting a photic sneeze. The experimental setup only elicited tickling sensations, but with further testing and optimisation, it is reasonable to assume that it would reliably induce photic sneezes, thereby opening further mechanistic study of this intriguing phenomenon.

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Photic Sneeze Reflex: Another Variant of the Trigeminocardiac Reflex?

Cited by 4 publications

References 89 publications

Planktonic sea urchin larvae change their swimming direction in response to strong photoirradiation

Planktonic sea urchin larvae change their swimming direction in response to strong photoirradiation

Biophysical parameters affecting lung surfactant function, surface tension and the transition from aerosol to droplet exhalation (in relation to COVID-19 infection)

Sneezing in response to bright light exposure: A case study in a photic sneezer

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