Direct evidence of trigeminal innervation of the cochlear blood vessels.
ABSTRACT This paper provides the first detailed description of the trigeminal innervation of the inner ear vasculature. This system provides a newly discovered neural substrate for rapid vasodilatatory responses of the inner ear to high levels of activity and sensory input. Moreover, this discovery may provide an alternative mechanism for a set of clinical disturbances (imbalance, hearing loss, tinnitus and headache) for which a central neural basis has been speculated. Iontophoretic injections of biocytin were made via a glass microelectrode into the trigeminal ganglion in guinea-pigs. Tissue for histological sections was obtained 24 h later. Labeled fibers from the injection site were observed as bundles around the ipsilateral spiral modiolar blood vessels, as individual labeled fibers in the interscala septae, and in the ipsilateral stria vascularis. The dark cell region of the cristae ampullaris in the vestibular labyrinth was also intensively labeled. No labeled fibers were observed in the neuroepithelium of the cristae ampullaris or the semicircular canals. These results confirm and localize an earlier indirect observation of the trigeminal ganglion projection to the cochlea. This innervation may play a role in normal vascular tone and in some inner ear disturbances, e.g., sudden hearing loss may reflect an abnormal activity of trigeminal ganglion projections to the cochlear blood vessels.
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ABSTRACT: OBJECTIVE: to establish whether skin micro blood flow can be modified by exposure to the radiofrequency waves emitted by a mobile phone when the latter is held against the jaw and ear. METHODS: Variations in skin micro blood flow and skin temperature in adult volunteers were simultaneously recorded with a thermostatic laser Doppler system during a 20-minute "radiofrequency" exposure session and a 20-minute "sham" session. The skin microvessels' vasodilatory reserve was assessed with a heat challenge at the end of the protocol. RESULTS: During the radiofrequency exposure session, skin micro blood flow increased (vs. baseline) more than during the sham exposure session. The sessions did not differ significant in terms of the skin temperature time-course response. The skin microvessels' vasodilatory ability was found to be greater during radiofrequency exposure than during sham exposure. CONCLUSIONS: Our results reveal the existence of a specific vasodilatory effect of mobile phone radiofrequency emission on skin perfusion. This article is protected by copyright. All rights reserved.Microcirculation (New York, N.Y.: 1994) 04/2013; · 2.37 Impact Factor
Article: Migraine and motion sensitivity.[Show abstract] [Hide abstract]
ABSTRACT: Purpose of Review: This article describes vestibular migraine and motion sensitivity. Migraine headache is often accompanied by dizziness or unsteadiness. A diagnosis of vestibular migraine requires that a patient meet International Headache Society criteria for migraine headache, have episodic or fluctuating symptoms highly suggestive of a balance disorder, have no recognized alternative neuro-otologic diagnosis, and experience migrainous symptoms during episodes of vertigo or imbalance. This article discusses these diagnostic criteria; the epidemiology of vestibular migraine; laboratory abnormalities in vestibular migraine; the pathophysiology of vestibular migraine; the treatment of vestibular migraine; comorbidities and overlap with other neuro-otologic disorders, including basilar artery migraine, Ménière disease, and anxiety disorders; and the genetics of vestibular migraine. This review also discusses motion sickness and motion sensitivity, including their relationship with migraine, pathophysiology, and treatment.Recent Findings: Recent findings regarding vestibular migraine include new nomenclature for the disorder, validation of diagnostic criteria, new ideas regarding pathophysiology, and reviews of small treatment trials.Summary: Vestibular migraine is becoming the preferred designation for a neuro-otologic disorder with a migrainous etiology that causes dizziness and disequilibrium. Criteria have been established for diagnosing this disorder. Although pathophysiology is as yet uncertain and randomized trials are lacking, treatment recommendations can be made. Motion sickness represents a condition often associated with migraine that can reduce quality of life.Continuum (Minneapolis, Minn.). 10/2012; 18(5 Neuro-otology):1102-17.
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ABSTRACT: Vestibular migraine is becoming recognised as a distinct clinical entity that accounts for a high proportion of patients with vestibular symptoms. A temporal overlap between vestibular symptoms, such as vertigo and head-movement intolerance, and migraine symptoms, such as headache, photophobia, and phonophobia, is a requisite diagnostic criterion. Physical examination and laboratory testing are usually normal in vestibular migraine but can be used to rule out other vestibular disorders with overlapping symptoms. The pathophysiology of vestibular migraine is incompletely understood but plausibly could include neuroanatomical pathways to and from central vestibular structures and neurochemical modulation via the locus coeruleus and raphe nuclei. In the absence of controlled trials, treatment options for patients with vestibular migraine largely mirror those for migraine headache.The Lancet Neurology 07/2013; 12(7):706-15. · 23.92 Impact Factor