0000000000522568
AUTHOR
Renato Corradetti
4-Aminopyridine (4AP) Enhances Acetylcholine Output from the Rat Cerebral Cortex in vivo
Publisher Summary This chapter discusses a study to analyze the effect of 4-aminopyridine (4AP) administration on cortical acetylcholine (ACh) output. The study was done on adult male Wistar rats under urethane or pentobarbital anesthesia. A small Perspex cylinder filled with eserinized Ringer solution was applied on the exposed cerebral cortex. The solution in the collecting cylinder was removed every 10 min and its ACh content was determined by bioassay on the dorsal muscle of the leech. In urethane anaesthetized rats, the control ACh output was 0.98 ± 0.16 ng/min/cm2 and the administration of 4AP (3 mg/kg i.p.) was followed by a rapid increase in ACh output lasting at least 40 min. The i…
Choline Fluxes to and from the Rat Cerebral Cortex Studied with the “Cup Technique” in Vivo
Since MacIntosh and Oborin (11) and later Mitchell (12) introduced the “cup technique” as a mean to study acetylcholine release from the cerebral cortex in vivo, this technique has been widely used for investigating the release of various neurotransmitters in anaesthetized as well as unanaesthetized mammals (2, 13, 14). Recently we proposed the “cup technique” as a way for studying the efflux of endogenous choline (Ch) from the rat cerebral cortex (4, 5) and to estimate changes in the extracellular concentration of Ch, if we consider the fluid filling the cup as an extension of the extracellular space.
EFFECTS OF 4-AMINOPYRIDINE ON ACETYLCHOLINE OUTPUT FROM THE CEREBRAL CORTEX OF THE RAT in vivo
Abstract 1 The effects of 4-aminopyridine (4AP) on the output of acetylcholine (ACh) from the cerebral cortex were investigated in unanaesthetized freely moving rats and in anaesthetized rats by means of the `cup technique'. ACh was determined by bioassay on the dorsal muscle of the leech. 2 In unanaesthetized rats intraperitoneal injection of 4AP (3 mg/kg) had no effect on the cortical output of ACh. 3 After injection of morphine (10 mg/kg s.c.), which depressed the spontaneous output of ACh, 4AP increased the cortical output to a level significantly higher than that determined before morphine injection. 4 In rats anaesthetized with either urethane or pentobarbitone, drugs known to decreas…