The Central Path of the Light Reflex via the Sympathetic Nerve in the Cat

Okada, Hiromasa; Nakano, Osamu; Okamoto, Kyoko; Nakayama, Kimihiro; Nisida, Isamu

doi:10.2170/jjphysiol.10.646

Cited by 14 publications

(7 citation statements)

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“…While the inhibitory effect of light on the sympathetic output to the pupil was demonstrated in the 1960s and 1970s, little experimental work has been done since then. Okada et al (13) demonstrated a connection between the pretectal area and the sympathetic preganglionic neurones projecting to the iris. The course of this pathway has not been investigated since then.…”

Section: Discussionmentioning

confidence: 99%

“…Early work by Okada et al (13) provided experimental evidence in support of the hypothesis that the light-inhibited sympathetic pathway to the pupil, like the light reflex pathway (14), might originate from the pretectum. These authors introduced serial brainstem lesions to disrupt this putative pathway in an anesthetized cat preparation.…”

Section: Light-inhibited Sympathetic Pathwaysmentioning

confidence: 97%

“…Early work has shown that light inhibits neuronal activity in efferent peripheral sympathetic fibers, recorded from both preganglionic (“sympathetic nerves”) (9–11) and postganglionic (long ciliary nerves) (12, 13) fibers, in cats. The reduction in discharge is linearly related to the intensity of the light stimulus (10).…”

Section: Light-inhibited Sympathetic Pathwaysmentioning

confidence: 99%

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Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Szabadi

2018

Front. Neurol.

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Pupil dilation is mediated by a sympathetic output acting in opposition to parasympathetically mediated pupil constriction. While light stimulates the parasympathetic output, giving rise to the light reflex, it can both inhibit and stimulate the sympathetic output. Light-inhibited sympathetic pathways originate in retina-receptive neurones of the pretectum and the suprachiasmatic nucleus (SCN): by attenuating sympathetic activity, they allow unimpeded operation of the light reflex. Light stimulates the noradrenergic and serotonergic pathways. The hub of the noradrenergic pathway is the locus coeruleus (LC) containing both excitatory sympathetic premotor neurones (SympPN) projecting to preganglionic neurones in the spinal cord, and inhibitory parasympathetic premotor neurones (ParaPN) projecting to preganglionic neurones in the Edinger-Westphal nucleus (EWN). SympPN receive inputs from the SCN via the dorsomedial hypothalamus, orexinergic neurones of the latero-posterior hypothalamus, wake- and sleep-promoting neurones of the hypothalamus and brain stem, nociceptive collaterals of the spinothalamic tract, whereas ParaPN receive inputs from the amygdala, sleep/arousal network, nociceptive spinothalamic collaterals. The activity of LC neurones is regulated by inhibitory α2-adrenoceptors. There is a species difference in the function of the preautonomic LC. In diurnal animals, the α2-adrenoceptor agonist clonidine stimulates mainly autoreceptors on SymPN, causing miosis, whereas in nocturnal animals it stimulates postsynaptic α2-arenoceptors in the EWN, causing mydriasis. Noxious stimulation activates SympPN in diurnal animals and ParaPN in nocturnal animals, leading to pupil dilation via sympathoexcitation and parasympathetic inhibition, respectively. These differences may be attributed to increased activity of excitatory LC neurones due to stimulation by light in diurnal animals. This may also underlie the wake-promoting effect of light in diurnal animals, in contrast to its sleep-promoting effect in nocturnal species. The hub of the serotonergic pathway is the dorsal raphe nucleus that is light-sensitive, both directly and indirectly (via an orexinergic input). The light-stimulated pathways mediate a latent mydriatic effect of light on the pupil that can be unmasked by drugs that either inhibit or stimulate SympPN in these pathways. The noradrenergic pathway has widespread connections to neural networks controlling a variety of functions, such as sleep/arousal, pain, and fear/anxiety. Many physiological and psychological variables modulate pupil function via this pathway.

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Section: Discussionmentioning

confidence: 99%

Section: Light-inhibited Sympathetic Pathwaysmentioning

confidence: 97%

Section: Light-inhibited Sympathetic Pathwaysmentioning

confidence: 99%

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Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Szabadi

2018

Front. Neurol.

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“…By determining the effects of selective lesions at various levels of the CNS on the light induced inhibition of pupillodilation in the long ciliary nerves of cats, Okada and colleagues (274) found that this light signal originated at the level of the pretectum, presumably from one of the retinorecipient nuclei contained within the pretectum. Further lesions in more caudal portions of the CNS suggested that the inhibitory light signal descended from the pretectum bilaterally to the pupillodilation centers of the spinal cord.…”

Section: Autonomic Control Of the Pupilmentioning

confidence: 99%

Autonomic Control of the Eye

McDougal

Gamlin

2014

Comprehensive Physiology

348

369

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The autonomic nervous system influences numerous ocular functions. It does this by way of parasympathetic innervation from postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia, and by way of sympathetic innervation from postganglionic fibers that originate from neurons in the superior cervical ganglion. Ciliary ganglion neurons project to the ciliary body and the sphincter pupillae muscle of the iris to control ocular accommodation and pupil constriction, respectively. Superior cervical ganglion neurons project to the dilator pupillae muscle of the iris to control pupil dilation. Ocular blood flow is controlled both via direct autonomic influences on the vasculature of the optic nerve, choroid, ciliary body, and iris, as well as via indirect influences on retinal blood flow. In mammals, this vasculature is innervated by vasodilatory fibers from the pterygopalatine ganglion, and by vasoconstrictive fibers from the superior cervical ganglion. Intraocular pressure is regulated primarily through the balance of aqueous humor formation and outflow. Autonomic regulation of ciliary body blood vessels and the ciliary epithelium is an important determinant of aqueous humor formation; autonomic regulation of the trabecular meshwork and episcleral blood vessels is an important determinant of aqueous humor outflow. These tissues are all innervated by fibers from the pterygopalatine and superior cervical ganglia. In addition to these classical autonomic pathways, trigeminal sensory fibers exert local, intrinsic influences on many of these regions of the eye, as well as on some neurons within the ciliary and pterygopalatine ganglia.

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“…Πράγματι έχουν απομονωθεί απλές νευρωνικές μονάδες στην προοροφιαία περιοχή σε γάτες που πυροδοτούν συνεχώς μόνο σε σκοτάδι («off» εκφορτίσεις) και αναστέλλονται τονικά με την παρουσία διάχυτου φωτός. Ηλεκτρική διέγερση αυτών των μονάδων ακολουθείται από διαστολή της κόρης, ακόμα και σε γάτες που το εγκεφαλικό τους στέλεχος έχει υποστεί εγκάρσια διατομή στην περιοχή της γέφυρας έτσι ώστε να διακοπεί η κατιούσα συμπαθητική οδός διαστολής της κόρης (Nisida et al, 1959;Cavaggioni et al, 1968;Smith et al, 1968 (Passatore, 1976a(Passatore, , 1976b(Passatore, , 1977Nishimo et al, 1976) ή από το μακρύ ακτινωτό νεύρο (Nisida e tal., 1960, Okada, 1960 αναστέλλονται όταν το φως είναι αναμμένο, και η αναστολή αίρεται όταν το φως σβήνει, και ακολουθεί διαστολή της κόρης. Το συνεργό οπτικό σύστημα (ιδιαίτερα ανεπτυγμένο σε επίμυες) και κυρίως οι συνδέσεις ανάμεσα στον αμφιβληστροειδή και τους υπερχιασματικούς πυρήνες θεωρείται ότι παίζουν ρόλο στη διαμεσολάβηση αυτής της αντίδρασης.…”

Section: ελάχιστη διάμετρος κόρηςunclassified

Ψυχοφυσιολογική Διερεύνηση Της Εκ Φόβου Αναστολής Του Φωτο-Αντανακλαστικού Στον Άνθρωπο

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The Central Path of the Light Reflex via the Sympathetic Nerve in the Cat

Cited by 14 publications

References 0 publications

Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Autonomic Control of the Eye

Ψυχοφυσιολογική Διερεύνηση Της Εκ Φόβου Αναστολής Του Φωτο-Αντανακλαστικού Στον Άνθρωπο

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