Sound stimulation-induced vasomotor reflex in the central artery of the rabbit ear.
Effects of sound stimulation on the central artery of the rabbit ear were studied as a somato-autonomic reflex. Vasoconstriction and dilatation, caused by metronome sound stimulation, were estimated from the temperature fluctuations in the central artery of the ear, measured by a thermistor. To enhance the detection of temperature rises, moderately high background levels of arterial tone were established by exposing the tips of the ears to water at a temperature of 10 degrees C or 5 degrees C, prior to sound stimulation. A fall in arterial temperature due to vasoconstriction was observed immediately after the start of the 1-min sound stimulation, with a subsequent temperature rise which overshot the original basal level due to vasodilatation. A positive correlation between the ear temperature before sound stimulation and the temperature fall (p < 0.01), and a negative correlation between the ear temperature and the temperature rise (p < 0.05) were obtained. The temperature fall was blocked by phenoxybenzamine (9 mg/kg, i.p., p < 0.01). The subsequent rise was not influenced by atropine (3 mg/kg, i.p.) or phenoxybenzamine, however, it was attenuated by hexamethonium (6 mg/kg, i.p., p < 0.05). The temperature fall at the beginning of sound stimulation was related to alpha-adrenergic mechanism. The subsequent temperature rise was thought to be related to parasympathetic mechanism, excluding cholinergic mechanism.
Takeoka
M
M
Department of Oto-laryngology, Shinshu University School of Medicine, Matsumoto, Japan.
Ueda
G
G
Taguchi
K
K
Ge
R L
RL
Terasawa
K
K
Tsuchiya
K
K
D000161:Acoustic Stimulation; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000502:physiology*; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology; D018678:Cholinergic Agents / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004431:Ear, External / Q000098:blood supply* / Q000187:drug effects; D005730:Ganglionic Blockers / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D018678:Cholinergic Agents; D018680:Cholinergic Antagonists; D005730:Ganglionic Blockers