Back to Search
Start Over
Sympathoexcitatory input from hypothalamic paraventricular nucleus neurons projecting to rostral ventrolateral medulla is enhanced after myocardial infarction.
- Source :
-
American journal of physiology. Heart and circulatory physiology [Am J Physiol Heart Circ Physiol] 2020 Dec 01; Vol. 319 (6), pp. H1197-H1207. Date of Electronic Publication: 2020 Sep 18. - Publication Year :
- 2020
-
Abstract
- Elevated sympathetic vasomotor tone seen in heart failure (HF) may involve dysfunction of the hypothalamic paraventricular nucleus neurons that project to the rostral ventrolateral medulla (PVN-RVLM neurons). This study aimed to elucidate the role of PVN-RVLM neurons in the maintenance of resting renal sympathetic nerve activity (RSNA) after myocardial infarction (MI). In male rats, the left coronary artery was chronically ligated to induce MI. The rats received PVN microinjections of an adeno-associated viral (AAV) vector encoding archaerhodopsin T (ArchT) with the reporter yellow fluorescence protein (eYFP). The ArchT rats had abundant distributions of eYFP-labeled, PVN-derived axons in the RVLM. In anesthetized ArchT rats with MI ( n = 12), optogenetic inhibition of the PVN-RVLM pathway achieved by 532-nm-wavelength laser illumination to the RVLM significantly decreased RSNA. This effect was not found in sham-operated ArchT rats ( n = 6). Other rat groups received RVLM microinjections of a retrograde AAV vector encoding the red light-drivable halorhodopsin Jaws (Jaws) with the reporter green fluorescence protein (GFP) and showed expression of GFP-labeled cell bodies and dendrites in the PVN. Laser illumination of the PVN at a 635 nm wavelength elicited significant renal sympathoinhibition in Jaws rats with MI ( n = 9) but not in sham-operated Jaws rats ( n = 8). These results indicate that sympathoexcitatory input from PVN-RVLM neurons is enhanced after MI, suggesting that this monosynaptic pathway is part of the central nervous system circuitry that plays a critical role in generating an elevated sympathetic vasomotor tone commonly seen with HF. NEW & NOTEWORTHY Using optogenetics in rats, we report that sympathoexcitatory input from hypothalamic paraventricular nucleus neurons that project to the rostral ventrolateral medulla is enhanced after myocardial infarction. It is suggested that this monosynaptic pathway makes up a key part of central nervous system circuitry underlying sympathetic hyperactivation commonly seen in heart failure.
- Subjects :
- Animals
Disease Models, Animal
Male
Medulla Oblongata metabolism
Neural Pathways metabolism
Neural Pathways physiopathology
Neuroanatomical Tract-Tracing Techniques
Optogenetics
Paraventricular Hypothalamic Nucleus metabolism
Rats, Sprague-Dawley
Sympathetic Nervous System metabolism
Heart Failure physiopathology
Kidney innervation
Medulla Oblongata physiopathology
Myocardial Infarction physiopathology
Paraventricular Hypothalamic Nucleus physiopathology
Sympathetic Nervous System physiopathology
Vasomotor System physiopathology
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1539
- Volume :
- 319
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Heart and circulatory physiology
- Publication Type :
- Academic Journal
- Accession number :
- 32946261
- Full Text :
- https://doi.org/10.1152/ajpheart.00273.2020