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Peripheral chemoreflex activation in conscious mice
Author(s) -
Burmeister Melissa A.,
Braga Valdir A.,
Sharma Ram V.,
Davisson Robin L.
Publication year - 2008
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.22.1_supplement.739.2
Subject(s) - bradycardia , peripheral chemoreceptors , medicine , atropine , heart rate , endocrinology , angiotensin ii , chemistry , stimulation , peripheral , anesthesia , reflex bradycardia , chemoreceptor , hypoxia (environmental) , reflex , blood pressure , receptor , carotid body , organic chemistry , oxygen
Peripheral chemoreceptor activation with potassium cyanide (KCN) in conscious rats produces a sympathoexcitatory/pressor response, bradycardia and tachypnoea, which are potentiated during hypertension (HTN). However, this reflex has not been studied in conscious mice. We hypothesized that stimulation of peripheral chemoreceptors would evoke similar cardiovascular (CV) responses in mice, which would be altered during HTN. Mice were instrumented with intravenous (i.v.) catheters for drug delivery, and heart rate and blood pressure were measured by telemetry. Compared to saline (n=6), i.v. KCN (0.03%, n=6) elicited a pressor response (KCN: 25±3; sal: 5±1 mmHg, p<0.05) followed by hypotension (KCN: −31±5; sal: −4±2 mmHg, p<0.05). KCN also produced marked bradycardia (KCN: −218±30; sal: −9±8 bpm, p<0.05). The depressor and bradycardic responses were abolished by pre‐treatment (pt) with atropine (i.p.) (4±1 mmHg & 20±35 bpm, p<0.05), and the pressor response was abolished by pt with prazosin (i.p.) (3±1 mmHg, p<0.05). Similar studies were performed in mice receiving angiotensin‐II (Ang‐II, 600 ng.kg −1 .min −1 , s.c., n=6). The CV responses to KCN were unaltered after 2‐wks of Ang‐II infusion when mice were maximally hypertensive. These studies are the first to characterize the chemoreflex in mice and propose a new animal model for studying hypoxia‐related diseases such as obstructive sleep apnea.