Body temperature (BT), respiratory frequency, the duration of the LCR and the duration of apnea have been plotted as functions of experimental conditions (‘Ctr1,’ control normothermia condition; ‘Hyp,’ hyperthermic condition; ‘Hyp+5′IRTX,’ hyperthermia after bilateral 100 nL microinjections of 65 μM 5′iodoresiniferatoxin; and ‘Ctr2,’ normothermic conditions after bilateral 100 nL microinjections of 65 μM 5′iodoresiniferatoxin. ‘*’ indicates P < 0.05 compared to mean of the initial control condition, and ‘NS’ indicates that no significant difference existed between the treatments indicated. Schematic cross-sections starting caudal to the obex of the neonatal piglet medulla are shown on the right side of the figure. The pair of injections marked by the asterisk marks the site of the injections in the animal from the left side of Fig. 1. Anatomical abbreviations: 7, facial nucleus; ROb, raphé obscurus; RP, raphé pallidus; DMX, dorsal vagal motor nucleus; ION, inferior olivary nucleus; NTS, nucleus of the solitary tract; AMB, nucleus ambiguus.