| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Internal Medicine- Gastroenterology, University of Michigan, Ann Arbor, MI, USA
2 Laboratory of Autonomic Neuroscience, Pennington Biomedical Research Center, Baton Rouge, LA, USA
3 Department of Internal Medicine- Gastroenterology, University of Michigan, Ann Arbor, MI, USA; Department of Physiology, University of Michigan, Ann Arbor, MI, USA
* To whom correspondence should be addressed. E-mail: Travagli{at}umich.edu.
The dorsal motor nucleus of the vagus (DMV) receives more noradrenergic terminals than any other medullary nucleus; few studies, however, have examined the effects of norepinephrine (NE) on DMV neurons. We used whole cell patch clamp recordings in thin slices to determine the effects of NE on DMV neurons identified according to their gastric projections, and immunohistochemical techniques were
employed to examine the distribution of tyrosine hydroxylase immunoreactive (TH-IR) fibers within the DMV. Of the DMV neurons tested, 25% were unresponsive to NE perfusion, while the remaining 75% responded to NE in a concentration-dependent manner with either an excitation (49%), an inhibition (26%) or an inhibition followed by an excitation (4%). Antrum/pylorus- and corpus-projecting neurons responded to NE with a similar percentage of excitatory (49% and 59%, respectively) and inhibitory (20% for both groups) responses. A lower percentage of excitatory (37%) and a higher percentage of inhibitory (36%)
responses were, however, observed in fundus-projecting neurons. In all groups, pretreatment with prazosin (100nM) or phenylephrine (10µM) antagonized or mimicked the NE-induced excitation, respectively. Conversely, pretreatment with yohimbine (10 µM) or UK-14304 (1µM) antagonized or mimicked the NE-induced inhibition, respectively. These data suggest that NE depolarization is mediated by 
1-adrenoceptors, while NE hyperpolarization is mediated by 2-adrenoceptors. In sixteen neurons depolarized by NE, the amplitude of the action potential afterhyperpolarization (AHP) and its kinetics of decay (
) were reduced by 13±0.7% and by 20±8% respectively (P<0.05 vs. control). No differences were found on the amplitude and of the AHP in neurons hyperpolarized by NE. Areas of significant difference in the TH-IR fiber density were observed within the mediolateral extent of the DMV; however, the mediolateral distribution of cells showing the different responses to NE did not show a pattern of localization.
This article has been cited by other articles:
|
|
 |
|
  M. A. Herman, M. Niedringhaus, A. Alayan, J. G. Verbalis, N. Sahibzada, and R. A. Gillis Characterization of noradrenergic transmission at the dorsal motor nucleus of the vagus involved in reflex control of fundus tone Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R720 - R729. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. G. Wilson, S. Akhter, C. A. Mayer, P. Kc, K. V. Balan, P. Ernsberger, and M. A. Haxhiu Allergic lung inflammation affects central noradrenergic control of cholinergic outflow to the airways in ferrets J Appl Physiol, December 1, 2007; 103(6): 2095 - 2104. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. F. Andrew, T. T. Dinh, and S. Ritter Localized glucoprivation of hindbrain sites elicits corticosterone and glucagon secretion Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2007; 292(5): R1792 - R1798. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Zheng and R. A. Travagli Dopamine effects on identified rat vagal motoneurons Am J Physiol Gastrointest Liver Physiol, April 1, 2007; 292(4): G1002 - G1008. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. N. Browning, Z. Zheng, T. W. Gettys, and R. A. Travagli Vagal afferent control of opioidergic effects in rat brainstem circuits J. Physiol., September 15, 2006; 575(3): 761 - 776. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Hermann, R. A. Travagli, and R. C. Rogers Esophageal-gastric relaxation reflex in rat: dual control of peripheral nitrergic and cholinergic transmission Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2006; 290(6): R1570 - R1576. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Honda, K. Ono, S. Kataoka, and K. Inenaga Activation of subfornical organ neurons in rats through pre- and postsynaptic {alpha}-adrenoceptors Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2006; 290(6): R1646 - R1653. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Ferreira Jr., N. Sahibzada, M. Shi, M. Niedringhaus, M. R. Wester, A. R. Jones, J. G. Verbalis, and R. A. Gillis Hindbrain chemical mediators of reflex-induced inhibition of gastric tone produced by esophageal distension and intravenous nicotine Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2005; 289(5): R1482 - R1495. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Hermann, J. S. Nasse, and R. C. Rogers {alpha}-1 adrenergic input to solitary nucleus neurones: calcium oscillations, excitation and gastric reflex control J. Physiol., January 15, 2005; 562(2): 553 - 568. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
