FAILURE OF THE METHOD OF PARALLEL BIOASSAY TO IDENTIFY ACETYLCHOLINE IN MIXTURES OF SUBSTANCES WITH ACETYLCHOLINE-LIKE ACTIVITY

1965 ◽  
Vol 43 (4) ◽  
pp. 657-662 ◽  
Author(s):  
E. A. Hosein ◽  
Teow Yan Koh
Keyword(s):  
Blood Pressure ◽  
Guinea Pig ◽  
Pharmacological Activity ◽  
Active Substance ◽  
Guinea Pig Ileum ◽  
Dorsal Muscle ◽  
Other Substances

The method of parallel bioassay used on the sensitized frog rectus, the dorsal muscle of the leech, the guinea pig ileum, and the cat's blood pressure has been studied to determine whether this method permits the identification of acetylcholine in mixtures of substances which possess acetylcholine-like activity. It was found that the method cannot identify acetylcholine in such mixtures, and in addition, the data obtained indicated that the method also failed to identify other substances with similar pharmacological activity, which were present in the mixtures. It was concluded that the method of parallel bioassay cannot be used to identify acetylcholine in extracts unless it is shown by other means that acetylcholine is the only active substance present in the material being assayed.

Pharmacological activity of a procyanidin isolated fromSclerocarya birrea bark: Antidiarrhoeal activity and effects on isolated guinea-pig ileum

1993 ◽  
Vol 7 (1) ◽  
pp. 25-28 ◽  
Author(s):  
J. Galvez ◽  
M. E. Crespo ◽  
A. Zarzuelo ◽  
P. De Witte ◽  
C. Spiessens
Keyword(s):  
Guinea Pig ◽  
Pharmacological Activity ◽  
Guinea Pig Ileum

Characterization of the Possible Mechanisms Underlying the Hypotensive and Spasmogenic Effects of Loranthus ferrugineus Methanolic Extract

2009 ◽  
Vol 37 (05) ◽  
pp. 991-1008 ◽  
Author(s):  
Omar Z. Ameer ◽  
Ibrahim M. Salman ◽  
Mohammad Jamshed A. Siddiqui ◽  
Mun F. Yam ◽  
Raghava N. Sriramaneni ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Guinea Pig ◽  
Blood Pressure Lowering ◽  
Sprague Dawley ◽  
Guinea Pig Ileum ◽  
Blood Pressure Lowering Effect ◽  
Appreciable Change ◽  
Lowering Effect ◽  
Pressure Lowering ◽  
Stimulation Of

In the present study, L. ferrugineus methanol extract (LFME) was evaluated for its blood pressure lowering effect in anesthetized normotensive Sprague Dawley (SD) rats and its spasmogenic effect in isolated guinea pig ileum. The possible mechanism(s) of action were also investigated. LFME was obtained by Soxhlet extraction. The rats were fasted overnight and anesthetized with sodium pentobarbitone (60 mg/kg i.p.). LFME was administered in i.v. boluses in the concentrations of 25, 50, 100 and 200 mg/kg respectively, with concomitant monitoring of mean arterial pressure (MAP). It was found that LFME dose-dependently reduced MAP. An i.v. bolus injection of atropine significantly decreased the blood pressure lowering effect of LFME. Similarly, L-NAME (Nω-nitro-L-arginine methyl ester) significantly lowered both the MAP and the action duration. Conversely, no significant change in MAP was seen following i.v. injections of neostigmine, hexamethonium, prazosin and propranolol. LFME also produced a dose-dependent contractile effect in guinea pig ileum. This contraction was significantly reduced in atropine pre-incubated tissue segments, yet it was significantly enhanced in the presence of neostigmine. No appreciable change in the ability of LFME to contract guinea pig ileum was seen in the presence of hexamethonium. Accordingly, it can be postulated that LFME possesses a marked hypotensive effect that can be attributed to stimulation of muscarinic receptors and/or stimulation of nitric oxide (NO) release. Moreover, LFME retains a considerable spasmogenic action due to its cholinergic properties. The hypotensive and spasmogenic effects of LFME justify its traditional uses.

scholarly journals Bioassay of derived components from venom of Iranian medically important scorpions to identify the bradykinin potentiating factors

2017 ◽  
Author(s):  
Hamid Reza Goudarzi ◽  
Ali Nazari ◽  
Mojtaba Noofeli ◽  
Maedeh Samiani
Keyword(s):  
Blood Pressure ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Guinea Pig ◽  
Angiotensin Converting Enzyme ◽  
High Performance ◽  
Organ Bath ◽  
Converting Enzyme ◽  
Guinea Pig Ileum ◽  
Rat Uterus

AbstractThe venom of animals, including snakes, scorpions and spiders is a complex combination of proteins, peptides, and other biomolecules as well as some minerals. Among the biomolecules, some peptides prevent converting of angiotensin 1 to angiotensin 2 by inhibiting of the Angiotensin Converting Enzyme (ACE) and finally reducing the blood pressure in the victims. The aim of the present study was to isolate venom components of the three species of Iranian medically important scorpions and to study the bradykinin potentiating effect of them. Separation of the venom components for each scorpion was carried out using high performance liquid chromatography (HPLC). The range of fractions (zones) obtained in several replicates on Guinea pig ileum and rat uterus tissues were performed using organ bath instrument. The bioassays were resulted in the peptides including Z1 and Z2 regions of venom chromatogram of the Hottentotta sulcyi, Z2 for Odontobutus doriea and Z2 and Z3 in Mesobutus eupeus venom demonstrated bradykinin potentiating effect.

Structure–activity studies on substance P

1979 ◽  
Vol 57 (12) ◽  
pp. 1427-1436 ◽  
Author(s):  
R. Couture ◽  
A. Fournier ◽  
J. Magnan ◽  
S. St-Pierre ◽  
D. Regoli
Keyword(s):  
Blood Pressure ◽  
Substance P ◽  
Guinea Pig ◽  
Free Acid ◽  
Biological Activities ◽  
Intrinsic Activity ◽  
Guinea Pig Ileum ◽  
Rat Blood ◽  
Mesenteric Vein ◽  
Structure Activity

A complete series of analogues of substance P (SP) in which L-Ala was used to replace the natural residues one by one, and the C-terminal free acid SP, were synthesized and tested in order to study the relationships between chemical structure and biological activities. All compounds were tested for their hypotensive effect on the rat blood pressure and for their myotropic activities on the guinea pig ileum, the rabbit anterior mesenteric vein, and the rat vas deferens.The results indicate that the first five residues from the amino end and Gly9 can be replaced by L-Ala without change of hypotensive or myotropic activities, but the substitution of the residues from the carboxyl end (Met11, Leu10, Phe8, and Phe7) with L-Ala brings about variable losses of affinity. All analogues maintain full intrinsic activity in the guinea pig ileum; [Ala10]-SP and [Ala11]-SP maintain more than 80% of intrinsic activity in the mesenteric vein, the other analogues being full agonists; moreover, [Ala7]-SP and [Ala 8]-SP show a weaker hypotensive potency than all other compounds. The effect of SP is not modified by an inhibitor of the converting enzyme (YS 980), but that of SP free acid is either potentiated (rabbit mesenteric vein, rat vas deferens) or not modified (rat blood pressure, guinea pig ileum).The findings presented in this paper are discussed in terms of structure–activity relationships. However, no clear indication has emerged as to the identity of the active group(s) or on a possible distinction between the molecular sequences or groups involved in binding or in stimulation of receptors by SP.

Role of histamine or other released substances in anaphylaxis in isolated guinea pig ileum

1959 ◽  
Vol 197 (1) ◽  
pp. 31-33 ◽  
Author(s):  
Murray Dworetzky
Keyword(s):  
Guinea Pig ◽  
Anaphylactic Reaction ◽  
Active Substance ◽  
Guinea Pig Ileum ◽  
Anaphylactic Contraction

A study was made of the role of histamine or other active liberated substances in anaphylaxis in isolated segments of guinea pig ileum. A technique was used by which it can be quantitatively estimated how much of the total anaphylactic reaction is due to liberation of such substances. The method consisted of suspending a segment from a sensitized animal in a 40-ml bath, together with a segment called the ‘indicator segment’, from a normal, nonsensitized animal. Thus, during anaphylactic contraction of the sensitized segment, histamine or any other active substance liberated into the bath would be expected to diffuse through the perfusion bath and cause a contraction of the so-called ‘indicator segment’. The height of the contractions was roughly estimated in terms of that amount of histamine necessary to cause a contraction of the same intensity. Using this technique, it was concluded that no more than 10% of the total anaphylactic contraction in the isolated sensitized guinea pig ileum can be accounted for by histamine or any other substance liberated into the bath fluid.

Inhibition of eledoisin by morin on the isolated guinea pig ileum

1968 ◽  
Vol 46 (1) ◽  
pp. 67-69 ◽  
Author(s):  
André L. Gascon
Keyword(s):  
Blood Pressure ◽  
Guinea Pig ◽  
Dose Response ◽  
The Other ◽  
Guinea Pig Ileum ◽  
Response Curves ◽  
Rat Blood ◽  
Other Hand ◽  
Noncompetitive Inhibitor ◽  
Dose Response Curves

The response of the isolated guinea pig ileum to angiotensin, bradykinin, eledoisin, and acetylcholine was studied before and during exposure to morin. Dose–response curves were made for each agonist in the presence of different concentrations of the flavonoid (1 to 8 μg/ml). Under these conditions, the responses of the ileum to eledoisin, angiotensin, and acetylcholine were modified to various degrees depending upon the concentration of morin. With morin 1 μg/ml, the effect of eledoisin was reduced, and the activity of this polypeptide progressively decreased with an increase in the concentration of the inhibitor. On the other hand, the activity of acetylcholine was potentiated while that of bradykinin and angiotensin was unchanged. With higher concentrations of morin (4 and 8 μg/ml), the effect of both angiotensin and acetylcholine was slightly reduced. On the rat blood pressure, morin did not modify the effect of agonists. From these results it is concluded that morin is a specific and noncompetitive inhibitor of eledoisin on the isolated guinea pig ileum.

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