Fig. 5. The respiratory (A ), mean blood pressure (B ), and heart rate (C ) responses to the brief hypoxia before and after 2.5 mM DAMGO was injected into the sites 1 mm lateral to the calamus scriptorius (n = 6). Data are presented as means ± SE. P < 0.05 are presented exactly and those more than 0.88 are not presented. f = breath frequency; HR = heart rate; MBP = mean blood pressure; VE= minute ventilation; VT= tidal volume. (D ) A representative slice showing the location of injection 1 mm right to the comNTS stained by fluorescent microbeads (red ). CC = central canal; comNTS = commissural part of the nucleus of the solitary tract (NTS); CuR = cuneate nucleus, rotundus part; DAMGO =[D-Ala2, N-MePhe4, Gly-ol]-enkephalin; Gr = gracile nucleus; 10N = dorsal vagal motor nucleus; 12N = hypoglossal nucleus.