title: Stress peptide PACAP stimulates and stabilizes neonatal breathing through distinct mechanisms.
abstract: Pituitary adenylate cyclase-activating peptide (PACAP) is an important mediator of the stress response and is crucial in maintaining breathing in neonates. Here we investigate the role of exogenously applied PACAP in neonatal breathing using the neonatal rat in situ working heart-brainstem preparation. A 1-min bolus of 250 nM PACAP-38 caused an increased in respiratory frequency that was rapid and transient, but had no effect on neural tidal volume or neural minute ventilation. Denervation of the carotid body abolished this effect. PACAP had a persistent effect on breathing stability in both carotid body-intact and -denervated preparations, as shown by decreases in respiratory variability 5 min following application. These data suggest that PACAP released during stress acts via carotid body dependent and independent mechanisms to stimulate and stabilize breathing. These mechanisms may account for PACAP's critical role in defending neonatal breathing against environmental stress.
authors.affiliation: Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
authors.forename: E V
authors.initials: EV
authors.lastname: Ferguson
authors.forename: A
authors.initials: A
authors.lastname: Roy
authors.forename: P
authors.initials: P
authors.lastname: Ciechanski
authors.forename: R J A
authors.initials: RJ
authors.lastname: Wilson
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000187:drug effects* / Q000502:physiology; D002344:Carotid Body / Q000187:drug effects / Q000502:physiology*; D003714:Denervation; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000494:pharmacology*; D012123:Pulmonary Ventilation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors
chemical_list: D051219:Pituitary Adenylate Cyclase-Activating Polypeptide