The hypothalamic oxytocin receptors in the paraventricular nucleus in autonomic cardiovascular control
Year: 2015
Type: dissertation
Abstract: The paraventricular nucleus (PVN) of the hypothalamus is an important integrative site of neuroendocrine control of the circulation. Herein I investigate the role of oxytocin receptors (OTRs) in the PVN in cardiovascular homeostasis. Experiments were performed in conscious male Wistar rats equipped with a radiotelemetric device. The PVN was unilaterally co-transfected with an adenoviral vector (Ad) engineered to over-express OTRs along with an enhanced green fluorescent protein (eGFP) tag. Control groups were PVN transfected with an Ad expressing eGFP alone or untransfected, sham rats (Wt). Rats were recorded without and with selective blockade of OTRs (OTX), both under baseline and stressful conditions. Baro-receptor reflex sensitivity (BRS) and cardiovascular short-term variability were evaluated using the sequence method and spectral methodology, respectively. Under baseline conditions OTR rats exhibited enhanced BRS and reduced blood pressure (BP) variability in comparison to eGFP and Wt rats. Exposure to stress increased BP, BP variability and heart rate (HR) in all rats. In eGFP and Wt rats, but not in OTR rats, BRS decreased during exposure to stress. Pre-treatment of OTR rats with OTX reduced BRS and enhanced BP and HR variability under baseline and stressful conditions. In Wt rats pre-treated with OTX, BRS was decreased and BP variability was increased under baseline and stress while HR variability was increased only during stress. OTRs in PVN are involved in tonic neural control of BRS and cardiovascular short-term variability. The failure of this mechanism could critically contribute to autonomic deregulation in cardiovascular disease.
Author: Maja Lozić Đurić
Language: Serbian
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3087058919