Paraventricular vasopressin-containing neurons project to brain stem and spinal cord respiratory-related sites.
We studied in the rat projections of vasopressin-containing neurons of the paraventricular nucleus (PVN) to phrenic nuclei and to the pre-Botzinger complex (pre-BotC). In addition, we determined vasopressin receptor expression within the pre-BotC and the physiological effects of vasopressin on respiratory drive and arterial blood pressure when injected into the pre-BotC. Retrograde tracing with cholera toxin B subunit (CT-b) showed that a subpopulation of vasopressin-containing PVN neurons project to phrenic nuclei and the pre-BotC. The latter region, identified by expression of neurokinin-1 receptors, contained a subpopulation of neurons that were immunoreactive for the vasopressin type 1 receptor (V(1)R). Microinjection of vasopressin in the pre-BotC (0.2 nmol/200 nl) significantly increased diaphragm electromyographic activity and frequency discharge (P<0.05). In addition, vasopressin increased blood pressure and heart rate (P<0.05). These data indicate that PVN vasopressin-containing neurons innervate respiratory-related regions of the medulla oblongata and spinal cord and when vasopressin is released at these sites, it may increase respiratory drive via activation of the distinct V(1)R.
Kc
Prabha
P
Specialized Neuroscience Research Program, Department of Physiology and Biophysics, Howard University College of Medicine, 520 W St. N.W., Washington, DC 20059, USA.
Haxhiu
Musa A
MA
Tolentino-Silva
Fatima P
FP
Wu
Mingfei
M
Trouth
C Ovid
CO
Mack
Serdia O
SO
D000818:Animals; D001933:Brain Stem / Q000737:chemistry / Q000502:physiology*; D008297:Male; D009434:Neural Pathways / Q000737:chemistry / Q000502:physiology; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration; D013116:Spinal Cord / Q000737:chemistry / Q000502:physiology*; D014667:Vasopressins / Q000032:analysis / Q000502:physiology*
D014667:Vasopressins