[Inhibitory effect of aminoglycoside antibiotics on rabbit carotid baroreceptor activity in vitro].
The present study was to investigate the effects of aminoglycoside antibiotics, changes in extracellular Ca2+ concentration and antagonists of L-type Ca-channels on the activity of rabbit carotid sinus baroreceptors (CS-BRA) in isolated and superperfused carotid sinus-carotid sinus nerve (CS-CNS) preparations, using extracellular recording technique. The results are as follows. (1) Streptomycin (0.25-0.75 mmol/L) and gentamycin (0.43-1.29 mmol/L) inhibited CS-BRA in a dose-dependent manner, which recovered after the drugs were washed out. (2) Perfusion with high Ca2+ (3.3 mmol/L) solution inhibited CS-BRA, while perfusate with trace Ca2+ (in the order of 10(-5) mol/L) increased it. (3) Verapamil and diltiazem had no effect on CS-BRA at a concentration of 10(-7) mol/L, but inhibited it at higher concentrations (> 10(-6) mol/L). These results suggest: (1) aminoglycoside antibiotics can inhibit CS-BRA specifically, thus providing a new tool for the study of baroreceptors; (2) calcium ions are not necessary for producing generator potentials of baroreceptors, and the L-type calcium channel does not seem to be involved in CS-BRA per se; and (3) the inhibitory effects of aminoglycoside antibiotics on CS-BRA may not be related to the blocking of L-type calcium channels.
Liu
D X
DX
Department of Cardiovascular Physiology, Capital University of Medical Sciences, Beijing 100054.
Niu
W Z
WZ
Shen
J
J
D000617:Aminoglycosides; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002346:Carotid Sinus / Q000294:innervation*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D066298:In Vitro Techniques; D011311:Pressoreceptors / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D002121:Calcium Channel Blockers; D002118:Calcium