Transmission by post-ganglionic axons of the autonomic nervous system: The importance of the specialized neuroeffector junction

Hirst, G. D. S.; Choate, Julia; Cousins, Helen M.; Edwards, Frank; Klemm, Megan F

doi:10.1016/0306-4522(96)00031-0

Cited by 57 publications

(52 citation statements)

References 121 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[23][24][25][26][27][28][29] The density of neuromuscular junctions was not increased by Ang II, suggesting that increases in ATP release are unlikely to be the cause of the increased sensitivity of the renal arcuate arteries to nerve stimulation after treatment. However, the low incidence of neuromuscular junctions and the possibility of a diffuse distribution of purinoceptors mean that this conclusion is made cautiously.…”

Section: Discussionmentioning

confidence: 95%

Selective Increase in Renal Arcuate Innervation Density and Neurogenic Constriction in Chronic Angiotensin II-Infused Rats

et al. 2004

View full text Add to dashboard Cite

Abstract-This study investigated the effects of angiotensin II "slow pressor" hypertension on structure and function of nerves supplying the renal vasculature. Low-dose angiotensin II (10 ng/kg per minute, initially sub-pressor) or saline vehicle was infused intravenously for 21 days in rats, and the effects were compared in renal and mesenteric arteries. Mean arterial pressure averaged 12Ϯ2 mm Hg higher than in vehicle-infused rats at 21 days. Using electron microscopy, the innervation density of renal arcuate, but not mesenteric arteries of equivalent size, was significantly higher in angiotensin II-infused than in vehicle-infused rats. Functional testing on a pressure myograph revealed that constrictions evoked by nerve stimulation in arcuate arteries were 2.3Ϯ0.7-fold greater in vessels from angiotensin II-infused compared with vehicle-infused rats (PϽ0.0001), whereas there was no significant difference in nerve-induced constrictions in mesenteric arteries. Sensitivity to and maximum amplitude of constrictions evoked by phenylephrine were not different in renal or mesenteric arteries between groups, suggesting that the increased neurally evoked constriction in renal arcuate arteries was not caused by postsynaptic changes. Endothelium-dependent vasorelaxation and the vessel wall physical properties were not different between the two groups in either artery. Thus, angiotensin II infusion appeared to evoke renal-specific increases in vessel innervation and increased vasoconstriction to nerve stimulation. These changes appear early and occur before changes in renal endothelial function are apparent. Thus, "slow pressor" angiotensin II hypertension is associated with increased renal innervation, compatible with a pathogenetic role.

show abstract

Section: Discussionmentioning

confidence: 95%

Selective Increase in Renal Arcuate Innervation Density and Neurogenic Constriction in Chronic Angiotensin II-Infused Rats

et al. 2004

View full text Add to dashboard Cite

show abstract

“…It should be noted, however, that bath application of carbachol may not accurately mimic release of endogenous neurotransmitters. Bath application of agonists may activate different populations of receptors from those activated at autonomic neuroeffector junctions (19) as has been reported in the guinea pig small intestine (10). This phenomenon could have contributed to differences in the features of myogenic and neurogenic events in rats and rabbits and the apparent absence of myogenic patterned activity in guinea pig and mouse.…”

Section: Myogenic Activity and Carbacholmentioning

confidence: 87%

Neurogenic and myogenic motor activity in the colon of the guinea pig, mouse, rabbit, and rat

Costa

Dodds

Wiklendt

et al. 2013

American Journal of Physiology-Gastrointestinal and Liver Physi

106

View full text Add to dashboard Cite

Costa M, Dodds KN, Wiklendt L, Spencer NJ, Brookes SJ, Dinning PG. Neurogenic and myogenic motor activity in the colon of the guinea pig, mouse, rabbit, and rat. Am J Physiol Gastrointest Liver Physiol 305: G749 -G759, 2013. First published September 19, 2013 doi:10.1152/ajpgi.00227.2013.-Gastrointestinal motility involves interactions between myogenic and neurogenic processes intrinsic to the gut wall. We have compared the presence of propagating myogenic contractions of the isolated colon in four experimental animals (guinea pig, mouse, rabbit, and rat), following blockade of enteric neural activity. Isolated colonic preparations were distended with fluid, with the anal end either closed or open. Spatiotemporal maps of changes in diameter were constructed from video recordings. Distension-induced peristaltic contractions were abolished by tetrodotoxin (TTX; 0.6 M) in all animal species. Subsequent addition of carbachol (0.1-1 M) did not evoke myogenic motor patterns in the mouse or guinea pig, although some activity was observed in rabbit and rat colon. These myogenic contractions propagated both orally and anally and differed from neurogenic propagating contractions in their frequency, extent of propagation, and polarity. Niflumic acid (300 M), used to block myogenic activity, also blocked neural peristalsis and thus cannot be used to discriminate between these mechanisms. In all species, except the mouse colon, small myogenic "ripple" contractions were revealed in TTX, but in both rat and rabbit an additional, higher-frequency ripple-type contraction was superimposed. Following blockade of enteric nerve function, a muscarinic agonist can evoke propulsive myogenic peristaltic contractions in isolated rabbit and rat colon, but not in guinea pig or mouse colon. Marked differences between species exist in the ability of myogenic mechanisms to propel luminal content, but in all species there is normally a complex interplay between neurogenic and myogenic processes. colon motility; enteric neurons; spatiotemporal maps; peristalsis COLONIC MOTILITY IS CONTROLLED by complex interactive processes in the gut, involving both nerve cells (neurogenic) and spontaneous muscle activity (myogenic). A number of studies have characterized fundamental mechanisms in the colon of the guinea pig, mouse, and rabbit and have shown that propagating contractions underlying peristalsis, or other propulsive motor patterns, require activity in the enteric nervous system (8,11,13,14,17,25).In recent papers, Huizinga et al. (20) and Chen et al. (7) produced evidence that challenges this principle. In the rat colon, in vitro, they showed that, after blocking peristalsis with antagonists of enteric neuronal activity [tetrodotoxin (TTX) or lidocaine], addition of a cholinergic agonist induced a recovery in propagating contractions. From these data they suggested that networks of interstitial cells of Cajal (ICC) work cooperatively with the enteric nervous system to create colonic motor patterns and that the main propulsive mechanism is the ...

show abstract

“…The functional implications of this are speculative. These varicosities may release transmitter, however, since there were no apparent specialised neuroeffector regions associated with these varicosities, which are suggestive of a specialised release site (see Hirst et al 1996 ;Luff, 1996), transmitter release may occur nonspecifically from all over the varicosity surface. The mixed receptor responses at 14 d may result from transmitter release at these sites.…”

Section: mentioning

confidence: 99%

“…Neurotransmitter release from these sites has been suggested to activate only a subset of receptors lying beneath the release site (Hirst & Neild, 1980 ; see also Hirst & Edwards, 1989 ;Hirst et al 1992Hirst et al , 1996Bennett et al 1998). Unfortunately, no detailed serial section ultrastructural studies have been performed during development and consequently, the number, proportion and characteristics of neuroeffector associations have not been described.…”

mentioning

confidence: 99%

“…Specialised neuroeffector associations have been described in a number of adult autonomic tissues (see Hirst et al 1996 ;Luff, 1996 ;Bennett et al 1998, for reviews). These studies have found that the majority of varicosities in autonomic tissues contain regions where the membranes of varicosities and the effector cells are closely apposed with synaptic vesicles being accumulated near these sites.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Specialised sympathetic neuroeffector associations in immature rat iris arterioles

Sandow

Hill

1999

Journal of Anatomy

View full text Add to dashboard Cite

Sympathetic nerve-mediated vasoconstriction in iris arterioles of mature rats occurs via the activation of α "Badrenoceptors alone, while in immature rat iris arterioles, vasoconstriction occurs via activation of both α " -and α # -adrenoceptors. In mature rats the vast majority of sympathetic varicosities form close neuroeffector junctions. Serial section electron microscopy of 14 d iris arterioles has been used to determine whether restriction in physiological receptor types with age may result from the establishment of these close neuroeffector junctions. Ninety varicosities which lay within 4 µm of arteriolar smooth muscle were followed for their entire length. Varicosities rarely contained dense cored vesicles even after treatment with 5-hydroxydopamine. 47 % of varicosities formed close associations with muscle cells and 88 % formed close associations with muscle cells or melanocytes. Varicosities in bundles were as likely as single varicosities to form close associations with vascular smooth muscle cells, although the distribution of synaptic vesicles in single varicosities did not show the asymmetric accumulation towards the smooth muscle cells seen in the varicosities in bundles which were frequently clustered together. We conclude that restriction of physiological receptor types during development does not appear to correlate with the establishment of close neuroeffector junctions, although changes in presynaptic structures may contribute to the refinement of postsynaptic responses.

show abstract

Transmission by post-ganglionic axons of the autonomic nervous system: The importance of the specialized neuroeffector junction

Cited by 57 publications

References 121 publications

Selective Increase in Renal Arcuate Innervation Density and Neurogenic Constriction in Chronic Angiotensin II-Infused Rats

Selective Increase in Renal Arcuate Innervation Density and Neurogenic Constriction in Chronic Angiotensin II-Infused Rats

Neurogenic and myogenic motor activity in the colon of the guinea pig, mouse, rabbit, and rat

Specialised sympathetic neuroeffector associations in immature rat iris arterioles

Contact Info

Product

Resources

About