We hypothesized that facilitation of respiratory rhythm by noradrenaline (NA) in rat pons-medulla-spinal cord preparations is mediated through α 1 -adrenergic receptors. In 0- to 4-day-old rats, the respiratory frequency (f R ) was monitored at the C4 ventral root and trigeminal motor (V MO ) outputs. f R at temperature (Te)=23°C was lower than that at a higher Te (27°C) and was increased by NA. At 23°C, lower concentrations of NA were needed to produce the same increases in f R seen at 27°C. With highest NA concentration we tested (50μM), activity at C4 was maintained in all preparations at both Te, whereas that at V MO was maintained in 50% (27°C) or 88% (23°C) of the preparations. Particularly, tonic activity at C4 appeared in all preparations at both Te, but that at the V MO occurred in 0% (27°C) or 18% (23°C) of the preparations. Based on these results, we used the lower Te (23°C) and applied a low concentration of NA (3μM) to the preparations. We found that: (1) with the addition of NA, f R was increased without the occurrence of tonic activity and (2) NA-related f R facilitation was inhibited by pre-treatment with the α 1 -adrenergic receptor antagonist prazosin (2μM). f R was increased by application of the α 1 -adrenergic receptor agonist phenylephrine (4μM), and this response was inhibited by prazosin (4μM). At Te=23°C, f R facilitation by NA in newborn rat pons-medulla-spinal cord preparations was obtained by activation of α 1 -adrenergic receptors.