[The effects of intravenous lidocaine on the activity of medullary respiratory neurons in cats].
The effects of intravenous lidocaine on the activity of medullary respiratory neuron were studied in urethane anesthetized cats. Using a tungsten microelectrode, spikes from medullary inspiratory neurons were recorded around nucleus ambiguous. Lidocaine was administered using a constant-rate infusion pump until electrographic seizures appeared. The effect of lidocaine on the activity of respiratory neurons showed two types. In one type, consisting of 7 units out of 10, a sequence of changes was observed: the initial stage was represented by increased duration of the burst and decreased frequency of neural discharge; the second stage by desynchronization with mechanical lung inflation; the third stage by continuous activity and the forth stage by decreased spike activity and electrographic seizures. Blood concentration of the lidocaine was 9.6 +/- 3.5 micrograms.ml-1 at the second stage, 15.3 +/- 4.4 micrograms.ml-1 at the third stage, 26.6 +/- 4.1 micrograms.ml-1 at the fourth stage. In another type, consisting of 3 units out of 10, following administration of lidocaine the number of spikes showed only a concentration related depression. Blood concentration of the lidocaine was 6.9 +/- 2.7 micrograms.ml-1 when the spikes disappeared. These results indicate that intravenous lidocaine influences the respiratory rhythm and produces the respiratory depression working in the central nervous system.
Kasaba
T
T
Kosaka
Y
Y
D000818:Animals; D002415:Cats; D007262:Infusions, Intravenous; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008526:Medulla Oblongata / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D012119:Respiration
D008012:Lidocaine