title: Developmental profile of cholinergic and purinergic traits and receptors in peripheral chemoreflex pathway in cats.
abstract: This study describes the developmental profile of specific aspects of cholinergic and purinergic neurotransmission in key organs of the peripheral chemoreflex: the carotid body (CB), petrosal ganglion (PG) and superior cervical ganglion (SCG). Using real time RT-PCR and Western blot analyses, we assessed both mRNA and protein expression levels for choline-acetyl-transferase (ChAT), nicotinic receptor (subunits alpha3, alpha4, alpha7, and beta2), ATP and purinergic receptors (P2X2 and P2X3). These analyses were performed on tissue from 1- and 15-day-old, 2-month-old, and adult cats. During development, ChAT protein expression level increased slightly in CB; however, this increase was more important in PG and SCG. In CB, mRNA level for alpha4 nicotinic receptor subunit decreased during development (90% higher in 1-day-old cats than in adults). In the PG, mRNA level for beta2 nicotinic receptor subunit increased during development (80% higher in adults than in 1-day-old cats). In SCG, mRNA for alpha7 nicotinic receptor levels increased (400% higher in adults vs. 1-day-old cats). Conversely, P2X2 receptor protein level was not altered during development in CB and decreased slightly in PG; a similar pattern was observed for the P2X3 receptor. Our findings suggest that in cats, age-related changes in cholinergic and purinergic systems (such as physiological expression of receptor function) are significant within the afferent chemoreceptor pathway and likely contribute to the temporal changes of O2-chemosensitivity during development.
authors.affiliation: Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada. Aida.bairam@crsfa.ulaval.ca
authors.forename: A
authors.initials: A
authors.lastname: Bairam
authors.forename: V
authors.initials: V
authors.lastname: Joseph
authors.forename: Y
authors.initials: Y
authors.lastname: Lajeunesse
authors.forename: R
authors.initials: R
authors.lastname: Kinkead
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western / Q000379:methods; D002344:Carotid Body / Q000254:growth & development / Q000378:metabolism; D002415:Cats; D002628:Chemoreceptor Cells / Q000254:growth & development* / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005726:Ganglia, Parasympathetic / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011983:Receptors, Purinergic / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D017783:Superior Cervical Ganglion / Q000254:growth & development / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D011950:Receptors, Cholinergic; D011983:Receptors, Purinergic; D000255:Adenosine Triphosphate; D002795:Choline O-Acetyltransferase