Neural mechanism of bradycardiac responses elicited by acupuncture-like stimulation to a hind limb in anesthetized rats.
The effects of acupuncture-like stimulation of a hind limb on heart rate were examined in anesthetized rats. An acupuncture needle, having a diameter of either 160 or 340 microm, was inserted into the skin and underlying muscles at a depth of about 5 mm and twisted right and left twice every second for 1 min. Stimulation by a needle with a diameter of either 160 or 340 microm produced a decrease in heart rate. Severance of the femoral and sciatic nerves ipsilateral to the hind-limb stimulation completely abolished the bradycardiac response. Also, heart rate was significantly decreased by acupuncture-like stimulation of the hind-limb muscles alone, but was not significantly influenced by the stimulation of the hind-limb skin alone. The bradycardiac response induced by acupuncture-like stimulation was not influenced by bilateral severance of the vagal nerves at the cervical level, but was abolished by bilateral stellectomy. Acupuncture-like stimulation of the hind limb induced a decrease in the activity of the cardiac sympathetic efferent nerve as well as a decrease in heart rate. These results indicate that the decrease in heart rate induced by acupuncture-like stimulation of a hind limb is a reflex response. The afferent pathway is composed of hind-limb muscle afferents, and the efferent pathway is composed of cardiac sympathetic nerves.
Uchida
Sae
S
Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
Shimura
Mayura
M
Ohsawa
Hideo
H
Suzuki
Atsuko
A
D026881:Acupuncture; D000758:Anesthesia; D000818:Animals; D001919:Bradycardia / Q000503:physiopathology*; D004525:Efferent Pathways / Q000502:physiology; D005267:Femoral Nerve / Q000293:injuries; D006321:Heart / Q000294:innervation / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006614:Hindlimb / Q000294:innervation / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000293:injuries; D012867:Skin / Q000294:innervation; D013564:Sympathetic Nervous System / Q000502:physiology; D061223:Vagus Nerve Injuries