scholarly journals Mechanism of action of substance P in guinea-pig ileum longitudinal smooth muscle: a re-evaluation.

1990 ◽  
Vol 431 (1) ◽  
pp. 529-541 ◽  
Author(s):  
J M Hall ◽  
I K Morton
Keyword(s):  
Smooth Muscle ◽  
Substance P ◽  
Guinea Pig ◽  
Mechanism Of Action ◽  
Guinea Pig Ileum ◽  
Longitudinal Smooth Muscle

scholarly journals Relationship between stimulated phosphatidic acid production and inositol lipid hydrolysis in intestinal longitudinal smooth muscle from guinea pig

1987 ◽  
Vol 244 (3) ◽  
pp. 763-768 ◽  
Author(s):  
R S E Mallows ◽  
T B Bolton
Keyword(s):  
Smooth Muscle ◽  
Small Intestine ◽  
Substance P ◽  
Guinea Pig ◽  
Phosphatidic Acid ◽  
Inositol Phosphates ◽  
Muscle Layer ◽  
Phospholipid Hydrolysis ◽  
Longitudinal Smooth Muscle ◽  
Inositol Phospholipid

Accumulation of [32P]phosphatidic acid (PA) and total [3H]inositol phosphates (IPs) was measured in the longitudinal smooth-muscle layer from guinea-pig small intestine. Stimulation with carbachol, histamine and substance P produced increases in accumulation of both [3H]IPs and [32P]PA over the same concentration range. The increase in [32P]PA accumulation in response to carbachol (1 microM-0.1 mM) was inhibited in the presence of atropine (0.5 microM). Buffering the external free [Ca2+] to 10 nM did not prevent the carbachol-stimulated increase in [32P]PA accumulation. Carbachol and Ca2+ appear to act synergistically to increase accumulation of [32P]PA. In contrast, although incubation with noradrenaline also increased accumulation of [3H]IPs, no increase in accumulation of [32P]PA could be detected. These results suggest that an increase in formation of IPs is not necessarily accompanied by an increase in PA formation, and imply the existence of receptor-modulated pathways regulating PA concentrations other than by phospholipase-C-catalysed inositol phospholipid hydrolysis.

The mechanism of action of ionophore A 23187 on guinea pig intestinal smooth muscle

1979 ◽  
Vol 57 (4) ◽  
pp. 348-358 ◽  
Author(s):  
Lois B. Rosenberger ◽  
D. J. Triggle
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Mechanism Of Action ◽  
Calcium Antagonists ◽  
Intestinal Smooth Muscle ◽  
Phase System ◽  
Muscarinic Agonist ◽  
Two Phase ◽  
Longitudinal Smooth Muscle ◽  
A 23187

The cation ionophore A 23187 behaves similarly to the potent muscarinic agonist, cis-2-methyl-4-dimethylaminomethyl-1,3-dioxolane methiodide (CD) in guinea pig ileal longitudinal smooth muscle generating contractile responses that are gradedly sensitive to the concentrations of Ca2+ext and Na+ext. A 23187 and CD responses are insensitive to tetrodotoxin and A 23187 responses are insensitive to atropine. The responses to CD, A 23187, and veratridine are all similarly sensitive to the calcium antagonists D 600 and BAY-1040. D 600 failed to antagonize the ability of A 23187 to transport Ca2+ in a toluene-butanol: water two-phase system. It is suggested that in guinea pig ileal smooth muscle A 23187 does not translocate Ca2+ext exclusively but serves also to activate Ca2+ channels perhaps by an initial depolarizing Na+ entry.

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