Reversible vagal blockade in conscious rats using a targeted delivery device.
Reversible methods of nerve blockade greatly aid neurophysiological and behavioral studies. We have developed an implantable device for the local delivery of anesthetics to the area surrounding the vagal nerve in rats. The device consists of a thick silicone tube for insulating the nerves from the surrounding tissue, and a thin silicone tube for the infusion of anesthetics into the insulating tube. The in vivo performance of the device was tested electrophysiologically, and cardiovascular responses to vagal stimulation were measured in conscious animals. Nerve conductivity was completely blocked by injection of a small amount (<20 microl) of 1% lidocaine, with conductivity subsequently recovering gradually after 10-40 min. Electrical stimulation of the right vagus nerve in conscious rats increased arterial pressure while decreasing heart rate. The local blockade of afferent fibers abolished the arterial pressure response but preserved the bradycardic response to vagal nerve stimulation. The targeted delivery device was useful for reversible vagal blockade in conscious rats.
Department of Cardiovascular Dynamics, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, Suita-shi, Osaka 565-8565, Japan. zhengcan@ri.ncvc.go.jp
Can
C
Zheng
Toru
T
Kawada
Meihua
M
Li
Takayuki
T
Sato
Kenji
K
Sunagawa
Masaru
M
Sugimachi
D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004558:Electric Stimulation; D004594:Electrophysiology; D005071:Evoked Potentials / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D015918:Infusion Pumps, Implantable; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology; D009407:Nerve Block; D009412:Nerve Fibers / Q000187:drug effects; D009431:Neural Conduction / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014630:Vagus Nerve / Q000187:drug effects*
D000779:Anesthetics, Local; D008012:Lidocaine