title: Failure in evoking the trigeminal cardiac reflex by mandibular stretching in healthy volunteers.
abstract: Stimulation of trigeminal sensory afferences has been reported to evoke hypotension and bradycardia, a phenomenon known as the trigeminal cardiac reflex. We attempted to evoke such a reflex through cycles of alternate mandibular stretching in healthy volunteers, as previously reported, for its possible therapeutic exploitation. In Phase 1 of the study, 10 healthy volunteers [5 male, 5 female, age (mean ± SD) 27±2 years)] underwent 2 randomized sessions of automated monitoring, every 6 minutes, of systolic blood pressure (SBP), diastolic (D) BP, and heart rate (HR), with a one-week interval, either with mandibular stretching (12 minutes with a spring device fitted in the mouth), or nothing (control). Observation was prolonged for 180 minute after the end of the stretching. In Phase 2, 7 other volunteers (4 male and 3 female, age 24±1.3 years) repeated the protocol with a sampling interval of 2 minutes until the end of stretching. Baseline levels of SBP, DBP and HR were similar in the test and control sessions. There was a progressive fall of BP and HR as a function of time during the test session. With stretching: SBP changed from 119.2±10.1 to 118.1±10.1 to 115.8±10.5 mmHg, at baseline, end of stretching and 180 minutes after, respectively, p<0.001 at ANOVA for time effect). However, similar changes occurred in the control group: from 120.7±12.0 to 120.8±12.0 to 115.4±3.6 mmHg at the same times, P=0.822 for group effect). In Phase 2, again we observed no significant changes for any of the parameters investigated as a function of treatment. Despite attempts at maximum standardization of study condition and the use of operator-independent BP and HR measurements, we could not detect significant BP or HR effects of repeated mandibular stretching.
authors.forename: Carlo
authors.initials: C
authors.lastname: De Innocentiis
authors.forename: Cristiano Giovannni
authors.initials: CG
authors.lastname: Caputi
authors.forename: Filomena
authors.initials: F
authors.lastname: Pinto
authors.forename: Stefania
authors.initials: S
authors.lastname: Quintiliani
authors.forename: Armando
authors.initials: A
authors.lastname: Meccariello
authors.forename: Giulia
authors.initials: G
authors.lastname: Renda
authors.forename: Marta
authors.initials: M
authors.lastname: Di Nicola
authors.affiliation: Institute of Cardiology, G. d'Annunzio University, Chieti-Pescara, c/o Cardiology Division, Ospedale SS. Annunziata, Chieti, Italy. Email: rdecater@unich.it.
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Caterina
authors.forename: Michele
authors.initials: M
authors.lastname: D'Attilio
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D064368:Healthy Volunteers; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008334:Mandible / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D012026:Reflex, Stretch / Q000502:physiology*; D014276:Trigeminal Nerve / Q000502:physiology*; D055815:Young Adult