Fig. 1

Effects of focal chemical stimulation of the HDB on extracellular ACh release in the olfactory bulb ipsilateral to the stimulation. a–c Diagram of the experiment demonstrating the microdialysis probe in the olfactory bulb (a and b), microinjection needle in the HDB, and the chromatogram of a 10-μl mixed solution containing the sample and internal standard (c isopropylhomocholine: IPHC). The ACh and IPHC peaks represent 68 fmol and 100 fmol measured by electrochemical detector after separation by HPLC. d, e The effects of focal chemical stimulation of the unilateral HDB on extracellular ACh release in the olfactory bulb. The level of ACh release in the perfusate every 3 min, measured by a microdialysis technique, is plotted on the ordinate. The onset of HDB stimulation is expressed as time zero on the abscissa. The upper horizontal bar indicates a microinjection of l-glutamate (50 nmol in 50 nl) into the HDB for 1 min. d Sample response in one rat. e Summary of the responses (n = 6). In each rat, one to two trials were summarized. Each column and vertical bar represent the mean ± SEM. * p < 0.05; significantly different from the pre-stimulus control values (−3 to 0 min) using a one-way repeated-measures ANOVA followed by a Dunnett’s multiple comparison test