Key result
Intrapericardial PBG and nicotine elicit sympathoinhibition via distinct epicardial afferent pathways.
Why the study?
The mechanisms and neural pathways mediating cardiac chemoreceptor responses via epicardial serotonin receptors in rats were not fully understood.
Population
Conscious and anesthetized Sprague-Dawley rats with intact, sinoaortic baroreceptor denervated, and vagotomized states
Comparison
Intrapericardial injection of Phenyl biguanide, nicotine, and serotonin (5-HT3) antagonist MDL 72222 versus isotonic saline vehicle
Design
Preclinical experimental study with chronic pericardial catheter implantation
Authors
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Hypothesis-generating for epicardial 5-HT3 modulation; anesthesia effects in rats leave human translation open.
Epicardial serotonin receptors mediate sympathoinhibitory responses via cardiac vagal afferents in rats, a response that is attenuated by anesthesia.
Veelken et al. (1990) studied this question. Intrapericardial phenyl biguanide (PBG) and nicotine (NIC) vs. Isotonic saline vehicle was evaluated on Arterial blood pressure, heart rate, right atrial pressure, respiratory rate, and renal nerve activity. Intrapericardial phenyl biguanide and nicotine elicit sympathoinhibitory responses mediated by epicardial receptors with different afferent neural pathways, with PBG acting via 5-HT3 receptors.
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