The identification of acetyl-l-carnitylcholine in rat brain extracts and the comparison of its cholinomimetic properties with acetylcholine

1970 ◽  
Vol 48 (10) ◽  
pp. 709-722 ◽  
Author(s):  
E. A. Hosein ◽  
A. Kato ◽  
E. Vine ◽  
A. M. Hill
Keyword(s):  
Guinea Pig ◽  
Rat Brain ◽  
Total Activity ◽  
Guinea Pig Ileum ◽  
Molar Basis ◽  
Choline Esters ◽  
Brain Extracts

Acetyl-l-carnitylcholine (l-ACCh) was identified in rat brain extracts on paper chromatograms developed in butanol–water for 138 h. l-ACCh was also identified in brain extracts fractionated on t.l.c. plates and on Sephadex G-10 columns. In every instance l-ACCh was separated from the acetylcholine (ACh) present and the ACh-like activity of l-ACCh was about 20% of the total activity in the extract. Both l-ACCh and ACh were found to be inseparable in a variety of chromatographic systems including electrophoresis. Treatment of these choline esters with cholinesterases showed that while true acetylcholinesterase hydrolyzed both l-ACCh and ACh, pseudocholinesterase destroyed only ACh. On a molar basis, the ACh-like activity of ACCh is one-half that of ACh on both the guinea pig ileum and frog rectus preparations. Like ACh, the ratio of the nicotinic to muscarinic potency of l-ACCh is unity. Mixtures of l-ACCh and ACh show summation of ACh-like activity on both the guinea pig ileum and frog rectus preparations.

scholarly journals Protein phosphatase composition in the smooth muscle of guinea-pig ileum studied with okadaic acid and inhibitor 2

1989 ◽  
Vol 262 (2) ◽  
pp. 617-623 ◽  
Author(s):  
A Takai ◽  
M Troschka ◽  
G Mieskes ◽  
A V Somlyo
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Okadaic Acid ◽  
Total Activity ◽  
Guinea Pig Ileum ◽  
Control Activity ◽  
Triton X ◽  
Type 1 Phosphatase ◽  
Intracellular Structure

Using okadaic acid, a potent inhibitor of type 2A and type 1 protein phosphatases, and inhibitor 2, an intrinsic inhibitory factor of type 1 phosphatase, we characterized the phosphorylated myosin light-chain (PMLC) phosphatase activity in the smooth-muscle extracts of guinea-pig ileum. In the intact fibres the control activity was 254 +/- 13 nmol of Pi/min per g wet wt. (n = 15) against 32P-labelled PMLC (4 microM) from chicken gizzard. The following phosphatase fractions were identified: an inhibitor-2-sensitive (type 1) fraction (fractional activity = 35%), a Mg2+-dependent and okadaic acid-insensitive (type 2C) fraction (17%), and two type 2A-like fractions that had different susceptibility to okadaic acid. The type 2A-like fraction with lower affinity to okadaic acid accounted for 30% of the control activity. After the cell membrane was permeabilized by Triton X-100, more than 60% of this fraction remained and accounted for about 90% of the total activity, whereas the other fractions were nearly abolished. The type 2A-like fraction may be bound to some intracellular structure such as contractile proteins.

Effects ofPassiflora edulis aqueous extracts on 5-HT3 receptors in guinea-pig ileum and rat brain

1995 ◽  
Vol 31 ◽  
pp. 266 ◽  
Author(s):  
M.D. Cotrim ◽  
M.A. Martins ◽  
I.V. Figueiredo ◽  
C. Cavadas ◽  
C.A. Fontes Rebeiro ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Rat Brain ◽  
Aqueous Extracts ◽  
Guinea Pig Ileum

scholarly journals [3H]-Mesulergine labels 5-HT7sites in rat brain and guinea-pig ileum but not rat jejunum

1999 ◽  
Vol 126 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Maggie Hemedah ◽  
Ian M Coupar ◽  
Fred J Mitchelson
Keyword(s):  
Guinea Pig ◽  
Rat Brain ◽  
Rat Jejunum ◽  
Guinea Pig Ileum

Structural requirements for opioid activity of analogues of the enkephalins

1977 ◽  
Vol 198 (1132) ◽  
pp. 249-265 ◽  
Keyword(s):  
Amino Acids ◽  
Guinea Pig ◽  
Rat Brain ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Vas Deferens ◽  
Proteolytic Enzymes ◽  
Opiate Receptor ◽  
Guinea Pig Ileum ◽  
Mouse Vas Deferens

Structure-activity relations of a series of analogues of the two endo­genous morphine-like peptides, leucine-enkephalin and methionine-enkephalin are examined on the basis of ( a ) effects on the mouse vas deferens and the guinea pig ileum and ( b ) affinities for the rat brain opiate receptor. In the mouse vas deferens, metabolism of the peptides by proteolysis is not a major influence on activity. In contrast, however, brain opiate re­ceptor preparations contain an abundance of proteolytic enzymes, the effects of which can be minimized by conducting opiate receptor binding assays at 0 °C and in the presence of bacitracin. The potentiation of biological activity and opiate receptor binding affinity by replacing the Gly 2 residue in the natural enkephalins by d-Ala, is discussed both in terms of increased stability of the Tyr-d-Ala bond to aminopeptidases and of the stabilization of the peptide conform­ation as present in the receptor-peptide complex. The substitution of the Leu 5 - or Met 5 -residue by the corresponding d-amino acid contributes little to proteolytic stability, which emphasizes that the predominating site at which metabolism occurs is the Tyr 1 -Gly 2 bond. Of the analogues described, [d-Ala 2 , d-Leu 5 ]-enkephalin is the most active peptide in the three assay systems, the mouse vas deferens, the guinea pig ileum and the rat brain opiate receptor preparations. Substitutions by the respective d-amino acids d-Tyr and d-Phe at positions 1 and 4 reduce both the potency and binding affinity and emphasize the importance of stereochemical acceptability at these positions. The promotion of receptor binding by d-amino acids is examined, particularly with respect to implied peptide conformations. The experi­mental data have been analysed for the relative influence of metabolic and conformational factors.

scholarly journals Effects of morphine-6-sulfate (M-6-S) on opioid receptors in both rat brain and isolated guinea-pig ileum.

1994 ◽  
Vol 64 ◽  
pp. 181
Author(s):  
Xintian Fan ◽  
Takao Taniguchi ◽  
Ken Kitamura ◽  
Kayoko Iwao ◽  
Kazuta Oguri ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Rat Brain ◽  
Opioid Receptors ◽  
Guinea Pig Ileum
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