scholarly journals THE LOCALIZATION OF ACETYLCHOLINESTERASE AT THE AUTONOMIC NEUROMUSCULAR JUNCTION

1967 ◽  
Vol 33 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Peter M. Robinson ◽  
Christopher Bell
Keyword(s):  
Enzyme Activity ◽  
Smooth Muscle ◽  
Neuromuscular Junction ◽  
Smooth Muscle Cells ◽  
Schwann Cells ◽  
Synaptic Vesicles ◽  
Muscle Cells ◽  
Acetylcholinesterase Activity ◽  
Bufo Marinus ◽  
Toad Bufo

Acetylcholinesterase has been localized at the autonomic neuromuscular junction in the bladder of the toad (Bufo marinus) by the Karnovsky method. High levels of enzyme activity have been demonstrated in association with the membranes of cholinergic axons and the adjacent membranes of the accompanying Schwann cells. The synaptic vesicles stained in occasional cholinergic axons. After longer incubation times, the membrane of smooth muscle cells close to cholinergic axons also stained. Axons with only moderate acetylcholinesterase activity or with no activity at all were seen in the same bundles as cholinergic axons, but identification of the transmitter in these axons was not possible.

Freeze-Etch Studies on the Innervation of Mesenteric Arteries and Vas Deferens

1971 ◽  
Vol 9 (2) ◽  
pp. 411-425
Author(s):  
C. E. DEVINE ◽  
F. O. SIMPSON ◽  
W. S. BERTAUD
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Schwann Cells ◽  
Synaptic Vesicles ◽  
Vas Deferens ◽  
Muscle Cells ◽  
Mesenteric Arteries ◽  
Axonal Membrane ◽  
Freeze Etching

The innervation of mesenteric arteries and vas deferens of guinea-pig and vas deferens of mouse was examined by freeze-etching. Axons in bundles at large distances from the smooth muscle cells, were invested by Schwann cells and contained mainly neurotubules, while axons close to the smooth muscle cells had varicosities up to 1.6 µm in diameter and 2.0 µm long containing mainly small (approximately 50 nm) and large (approximately 100 nm) synaptic vesicles. Vascular axons differed from those in the vas deferens in that the former were at the medial adventitial border with an observed closest neuromuscular distance of approximately 200 nm and the latter were between smooth muscle cells at distances of 20-50 nm. Depressions of the axonal surface were seen and particles up to 15 nm were found on the axonal membrane.

Rectifying properties of the membrane of single freshly isolated smooth muscle cells

1980 ◽  
Vol 239 (5) ◽  
pp. C175-C181 ◽  
Author(s):  
J. J. Singer ◽  
J. V. Walsh
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Smooth Muscle Cells ◽  
Fold Increase ◽  
Muscle Cells ◽  
Tetraethylammonium Chloride ◽  
Intracellular Microelectrodes ◽  
Toad Bufo ◽  
Isolated Smooth Muscle Cells ◽  
Direct Microscopic Observation

Single smooth muscle cells freshly isolated from the stomach muscularis of the toad Bufo marinus were studied under direct microscopic observation using intracellular microelectrodes. The deviation of the membrane potential from rest was recorded when steps of current were injected into the cell. Outward-going rectification was consistently observed both in the presence of 1.8 mM and higher external concentrations of Ca2+. There was no indication of inward-going rectification even under conditions favoring its demonstration, i.e., when the external concentration of K+ was high (108 mM) and Cl-, low (39.6 mM). In the presence of tetraethylammonium chloride (TEA), there was a marked decrease in the rectification normally observed with depolarizing currents, suggesting that a K+ conductance contributes to the outward-going rectification. This K+ conductance increased by almost two orders of magnitude over the range from -20 to 0 mV, and displayed an e-fold increase with a depolarization as small as 4-7 mV. In response to hyperpolarizing currents, the membrane potential did not always reach a plateau but at times continued to become more negative. The feasibility of the depletion of ions from the caveolae as an explanation for this observation is discussed.

scholarly journals Transforming growth factor-β1 increases lysyl oxidase enzyme activity and mRNA in rat aortic smooth muscle cells

1997 ◽  
Vol 25 (3) ◽  
pp. 446-452 ◽  
Author(s):  
Charles J. Shanley ◽  
Mehrnaz Gharaee-Kermani ◽  
Rajabrata Sarkar ◽  
Theodore H. Welling ◽  
Andrew Kriegel ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Transforming Growth Factor ◽  
Lysyl Oxidase ◽  
Muscle Cells ◽  
Transforming Growth Factor Β1 ◽  
Aortic Smooth Muscle ◽  
Oxidase Enzyme

Calcium transients and resting levels in isolated smooth muscle cells as monitored with quin 2

1986 ◽  
Vol 250 (5) ◽  
pp. C779-C791 ◽  
Author(s):  
D. A. Williams ◽  
F. S. Fay
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Time Course ◽  
Contractile Activity ◽  
Single Cells ◽  
Muscle Cells ◽  
Contractile Responses ◽  
A Value ◽  
Maximal Dosage ◽  
Toad Bufo

The Ca2+-sensitive dye quin 2 was used to monitor Ca2+ levels and to follow Ca2+ transients in suspensions of isolated toad (Bufo marinus) smooth muscle cells, whose contractile activity was monitored with a Coulter counter. Single cells were not utilized to follow Ca2+ changes involved with contraction because of problems of rapid dye bleaching and due to photosensitization of smooth muscle cells loaded with quin 2. High levels of quin 2 loading (2-5 mM) severely prolonged (time course increase greater than 3 times), or completely inhibited, contractile responses to carbachol or potassium depolarization. Lower levels (less than 1 mM) produced adequate fluorescent signals, even at the single cell level, and allowed contractile responses of normal magnitude, although with somewhat prolonged (2-3 times) time course. Resting Ca2+ concentrations determined using quin 2 at these lower levels were 129 +/- 3 nM, a value that closely coincided with that measured in the same cell type using Ca-sensitive microelectrodes, or an alternate, more highly fluorescent dye, Fura-2. Resting Ca2+ was highly dependent on the extracellular Ca2+ concentration that appeared to effect intracellular Ca2+ (Cai2+) both by altering the driving force on Ca2+ cross the membrane, as well as the Ca2+ permeability of the cell itself. A small but significant relaxation was observed in response to the lowering of cytoplasmic Ca2+ below resting levels. After carbachol or K+ addition, fluorescent transients peaked significantly before the onset of contraction, which was also transient. Isoproterenol, a known relaxant of these cells, caused a small decrease in Cai2+ (approximately 40 nM) below rest, when applied in maximal dosage (10(-4) M). Isoproterenol also consistently diminished the Ca2+ transient induced by excitatory stimuli such as carbachol or K+. These results indicate that changes in contractility may be directly linked to changes in free cytoplasmic Ca2+ in smooth muscle cells.

Contraction of Single Smooth Muscle Cells from Bufo marinus Stomach

Nature ◽  
1971 ◽  
Vol 234 (5328) ◽  
pp. 351-352 ◽  
Author(s):  
ROLAND M. BAGBY ◽  
ALICE M. YOUNG ◽  
ROBERT S. DOTSON ◽  
BRUCE A. FISHER ◽  
KAREN MCKINNON
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Bufo Marinus

scholarly journals FINE STRUCTURAL LOCALIZATION OF CHOLINESTERASE ACTIVITY IN THE RAT SUBMANDIBULAR GLAND

1970 ◽  
Vol 18 (10) ◽  
pp. 730-739 ◽  
Author(s):  
BRUCE I. BOGART
Keyword(s):  
Smooth Muscle ◽  
Schwann Cell ◽  
Smooth Muscle Cells ◽  
Submandibular Gland ◽  
Muscle Cells ◽  
Acetylcholinesterase Activity ◽  
Myoepithelial Cells ◽  
Rat Submandibular Gland ◽  
Cell Interface ◽  
Axonal Swellings

The innervation of the rat submandibular gland was investigated by means of electron microscopy and cytochemical techniques. Axonal swellings partially depleted of their Schwann cell investment were observed in relationship to myoepithelial cells, acinar cells, ducts, capillaries and smooth muscle cells of arterioles. No direct contacts were found to exist between these elements and the nerve fibers. Axonal swellings containing mitochondria and vesicles fell into two distinct types: those characterized by small agranular vesicles and larger vesicles with pale cores and those characterized by small agranular vesicles and small vesicles with dense cores. Reaction product due to acetylcholinesterase activity was observed to be associated with the axolemma and the Schwann cell membrane at the axon-Schwann cell interface of many unmyelinated nerves found in relationship to both the vascular and parenchymal elements of the gland. Activity was found in association with the surface pits and vesicles of myoepithelial cells and arteriolar smooth muscle cells and with the rough endoplasmic reticulum and the nuclear envelope of the myoepithelial cells. Axonal swellings devoid of activity were observed particularly in relationship to arterioles. Reaction product was found only at the axon-Schwann cell interface when sections were incubated in medium for the demonstration of butyrylcholinesterase activity, while no reaction product was found upon addition of eserine sulfate to any of the media. The possibility that the reaction product due to acetylcholinesterase activity observed in association with the axolemma and the surface vesicles and pits of the myoepithelial cells and the arteriolar smooth muscle cells may define the autonomic cholinergic junction in the rat submandibular gland was explored.

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