| First Author | Barrett KT | Year | 2021 |
| Journal | Am J Physiol Regul Integr Comp Physiol | Volume | 320 |
| Issue | 2 | Pages | R116-R128 |
| PubMed ID | 33146556 | Mgi Jnum | J:300353 |
| Mgi Id | MGI:6502030 | Doi | 10.1152/ajpregu.00161.2020 |
| Citation | Barrett KT, et al. (2020) Impaired cardiorespiratory responses to hypercapnia in neonatal mice lacking PAC1 but not VPAC2 receptors. Am J Physiol Regul Integr Comp Physiol |
| abstractText | The evidence is mounting for a role for abnormal signaling of the stress peptide, pituitary adenylate cyclase activating polypeptide (PACAP), and its canonical receptor, PAC1, in the pathogenesis of sudden infant death syndrome (SIDS). In this study, we investigated whether the PACAP receptors, PAC1 or VPAC2, are involved in the neonatal cardiorespiratory response to hypercapnic stress. We used head-out plethysmography and surface ECG electrodes to assess cardiorespiratory responses to an 8% hypercapnic challenge in unanesthetized and spontaneously breathing 4 days old PAC1 or VPAC2 knockout (KO) and wildtype (WT) mouse pups. We demonstrate that compared to WTs, breathing frequency (RR) and minute ventilation () in PAC1 KO pups were significantly blunted in response to hypercapnia. Although heart rate was unaltered in PAC1 KO pups during hypercapnia, heart rate recovery post-hypercapnia was impaired. In contrast, cardiorespiratory impairments in VPAC2 KO pups were limited to only an overall higher tidal volume (VT), independent of treatment. These findings suggest that PACAP signaling through the PAC1 receptor plays a more important role than signaling through the VPAC2 receptor, in neonatal respiratory responses to hypercapnia. Thus, deficits in PACAP signaling primarily via PAC1 may contribute to the inability of infants to mount an appropriate protective response to homeostatic stressors in childhood disorders such as SIDS. |
