| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536-0298, USA
2 Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78229, USA
The present study sought to determine whether individual neurones of the median preoptic nucleus (MnPO) with axonal projections to the hypothalamic paraventricular nucleus (MnPO-PVN) respond to osmotic, circulating angiotensin II (Ang II), and baroreceptor stimulation. Hypertonic NaCl (0.75 or 1.5 osmol l–1) or Ang II (150 ng) was injected into the internal carotid artery (ICA). Baroreceptor stimulation was performed by I.V. injection of phenylephrine or sodium nitroprusside to increase or decrease arterial blood pressure, respectively. Of 65 MnPO neurones, 50 units were antidromically activated from the PVN with an average onset latency of 11.3 ± 0.7 ms. Only 9.5% of MnPO-PVN neurones were antidromically activated from the PVN bilaterally. Type I MnPO-PVN neurones (n = 14) responded to osmotic but not Ang II stimulation. In 79% (11/14) of these type I neurones, the response was an increase in cell discharge. Type II MnPO-PVN neurones (n = 7) displayed a significant increase in cell discharge in response to ICA injection of Ang II but not hypertonic NaCl. Type III MnPO-PVN neurones (n = 16) responded to both ICA injection of hypertonic NaCl and Ang II. In 88% (14/16) of type III neurones, osmotic and Ang II stimulation each increased cell discharge. Type IV MnPO-PVN neurones (n = 13) displayed no change in cell discharge in response to ICA injection of hypertonic NaCl or Ang II. Baroreceptor stimulation altered the discharge in subpopulations of type I, II and III MnPO-PVN neurones (43–63% depending on neuronal type). Only one MnPO-PVN neurone responded solely to baroreceptor stimulation (type IV). In addition, a subset of type I, II and III neurones displayed a significant correlation with sympathetic nerve activity and/or the cardiac cycle. These findings suggest that a significant population of MnPO-PVN neurones respond to osmotic and circulating Ang II stimulation and thereby represents a neural substrate through which neurohumoral inputs are integrated within the forebrain lamina terminalis.
(Received 8 July 2005;
accepted after revision 3 August 2005;
first published online 4 August 2005)
Corresponding author S. D. Stocker: Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40526-0298, USA. Email: sdstoc3{at}email.uky.edu
This article has been cited by other articles:
|
|
 |
|
  I. Matsumoto, Y. Inoue, T. Shimada, T. Matsunaga, and T. Aikawa Stimulation of brain mast cells by compound 48/80, a histamine liberator, evokes renin and vasopressin release in dogs Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R689 - R698. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Frithiof, S. Eriksson, F. Bayard, T. Svensson, and M. Rundgren Intravenous hypertonic NaCl acts via cerebral sodium-sensitive and angiotensinergic mechanisms to improve cardiac function in haemorrhaged conscious sheep J. Physiol., September 15, 2007; 583(3): 1129 - 1143. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Haley and F. W. Flynn Tachykinin NK3 receptor contribution to systemic release of vasopressin and oxytocin in response to osmotic and hypotensive challenge Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R931 - R937. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. McMullan, A. K. Goodchild, and P. M. Pilowsky Circulating angiotensin II attenuates the sympathetic baroreflex by reducing the barosensitivity of medullary cardiovascular neurones in the rat J. Physiol., July 15, 2007; 582(2): 711 - 722. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Kolaj and L. P. Renaud Presynaptic {alpha}-adrenoceptors in median preoptic nucleus modulate inhibitory neurotransmission from subfornical organ and organum vasculosum lamina terminalis Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2007; 292(5): R1907 - R1915. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. L. Freeman and V. L. Brooks AT1 and glutamatergic receptors in paraventricular nucleus support blood pressure during water deprivation Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1675 - R1682. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Suntsova, R. Guzman-Marin, S. Kumar, Md. N. Alam, R. Szymusiak, and D. McGinty The Median Preoptic Nucleus Reciprocally Modulates Activity of Arousal-Related and Sleep-Related Neurons in the Perifornical Lateral Hypothalamus J. Neurosci., February 14, 2007; 27(7): 1616 - 1630. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. R. Antunes, S. T. Yao, A. E. Pickering, D. Murphy, and J. F. R. Paton A spinal vasopressinergic mechanism mediates hyperosmolality-induced sympathoexcitation J. Physiol., October 15, 2006; 576(2): 569 - 583. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
