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Paraventricular nucleus mediates pressor response to noradrenaline injection into the dorsal periaqueductal gray area.
- Source :
-
Autonomic neuroscience : basic & clinical [Auton Neurosci] 2009 Dec 03; Vol. 151 (2), pp. 74-81. Date of Electronic Publication: 2009 Jun 28. - Publication Year :
- 2009
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Abstract
- The dorsal periaqueductal gray area (dPAG) is involved in cardiovascular modulation. In a previous study, we reported that noradrenaline (NA) microinjection into the dPAG of rats caused pressor response that was mediated by vasopressin release. Vasopressin is synthesized by magnocellular neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei. In the present study, we verified which nuclei mediated the cardiovascular response to NA as well as the existence of direct neural projection from the dPAG to hypothalamic nuclei. Then, we studied the effect of treating either PVN or SON with the nonselective synaptic blocker cobalt chloride (1mM) on the cardiovascular response to NA (15 nmol) microinjection into dPAG. Attempting to identify neural projections from dPAG to hypothalamic nuclei, we microinjected the neuronal tracer biotinylated-dextran-amine (BDA) into the dPAG and searched varicosity-containing nerve terminals in the PVN and SON. Unilateral cobalt-induced inhibition of synapses in the SON did not affect the cardiovascular response to NA. However, unilateral inhibition of PVN significantly reduced the pressor response to NA. Moreover, cobalt-induced inhibition of synapses in both PVN blocked the pressor response caused by NA microinjected into the dPAG. Microinjection of BDA into the dPAG evidenced presence of varicosity-containing neuronal fibers in PVN but not in SON. The results from cobalt treatment indicated that synapses in PVN mediate the vasopressin-induced pressor response caused by NA microinjection into the dPAG. In addition, the neuroanatomical results from BDA microinjection into the dPAG pointed out the existence of direct neural projections from the dPAG site to the PVN.
- Subjects :
- Animals
Antimutagenic Agents pharmacology
Autonomic Pathways drug effects
Autonomic Pathways metabolism
Biotin analogs & derivatives
Blood Pressure drug effects
Cobalt pharmacology
Dextrans
Male
Microinjections
Neural Pathways drug effects
Neural Pathways metabolism
Neuronal Tract-Tracers
Norepinephrine pharmacology
Paraventricular Hypothalamic Nucleus drug effects
Periaqueductal Gray drug effects
Presynaptic Terminals drug effects
Presynaptic Terminals metabolism
Rats
Rats, Wistar
Reflex drug effects
Reflex physiology
Supraoptic Nucleus drug effects
Supraoptic Nucleus metabolism
Sympathetic Nervous System drug effects
Sympathetic Nervous System metabolism
Vasoconstriction drug effects
Blood Pressure physiology
Norepinephrine metabolism
Paraventricular Hypothalamic Nucleus metabolism
Periaqueductal Gray metabolism
Vasoconstriction physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1872-7484
- Volume :
- 151
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Autonomic neuroscience : basic & clinical
- Publication Type :
- Academic Journal
- Accession number :
- 19564136
- Full Text :
- https://doi.org/10.1016/j.autneu.2009.06.005