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Effects of local microejection of biogenic amines into the pre‐Botzinger complex (pBC) and adjacent ventral respiratory column (VRC) on the canine breathing pattern
Author(s) -
Radocaj Tomislav,
Mustapic Sanda,
Stucke Astrid G.,
Stuth Eckehard A.,
Zuperku Edward J.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.960.7
Subject(s) - agonist , microinjections , serotonin , 5 ht receptor , chemistry , medicine , endocrinology , anesthesia , central nervous system , receptor
Previous studies suggest the presence of serotonin (5HT), dopamine (DA), and adrenergic receptors within the pBC region, but where these neuromodulators produce their principal effects on breathing remains unclear. The effects of local microinjections of 5HT (5mM), norepinephrine (NE; 5mM) and DA (5mM) into the VRC including the pBC on inspiratory (TI) and expiratory durations (TE) and peak phrenic activity (PPA) were studied in decerebrate, vagotomized, ventilated, paralyzed dogs (n=6). The locations of the VRC and pBC were determined by neuronal recordings and phrenic responses to glutamate agonist DLH (20mM, ~40 nl) microinjections. Unilateral injections (~100 nl) were made in 1 mm increments from the obex to 7mm rostral. The selective 5HT2a agonist (DOI, 0.2mM) and 5HT1a agonist (8OH‐DPAT, 0.2mM) were used in a similar protocol (n=7) and subsequently given iv. All amine agonists produced no significant changes in TI, TE, and PPA at any location within the VRC, while DLH injections produced significant changes. DOI (256 mcg/kg iv) produced a 10.3±5.4% increase in TI with no changes in TE and PPA, while 8OH‐DPAT (74 mcg/kg iv) decreased TI and TE to 67.1±4.5% and 62.3±7.2%, respectively with no change in PPA. These data suggest that the exogenous biogenic amines produce their effects on the breathing pattern at locations outside the VRC and pBC in dogs. Supported by VA Med. Res. and NIH GM059234 funds.