The anti‐inflammatory effect of catecholamines in the peritoneal cavity and hind paw of the mouse

1 Bradykinin-induced increased plasma protein extravasation (IPPE) and blood flow have been assessed in guinea-pig skin by isotopic methods. 2 The effects of a range of adrenoceptor agonists on these parameters have been investigated. 3 a-Adrenoceptor agonists inhibited IPPE and reduced cutaneous blood flow. The potency of a-agonists as inhibitors of IPPE correlated with their vasoconstrictor effects. The actions of noradrenaline on both IPPE and blood flow were blocked by phentolamine but not by propranolol.4 P-Adrenoceptor agonists inhibited IPPE at doses which either increased or caused little change in cutaneous blood flow. Isoprenaline inhibition of IPPE was reduced by propranolol but was unaffected by phentolamine. 5 The inhibitory action of a-agonists on IPPE can be explained by a reduction in blood flow to the affected site. Beta agonist inhibition is not due to effects on blood flow but is probably caused by a reduction in permeability of the microvessels.

Section: Cutaneous Bloodflowsupporting

confidence: 63%

mentioning

confidence: 92%

See 1 more Smart Citation

Actions of Locally Administered Adrenoceptor Agonists on Increased Plasma Protein Extravasation and Blood Flow in Guinea‐pig Skin

Beets¹,

Paul²

1980

“…In the model of gastric ulcer production by histamine, treatment with salbutamol also elicited a clear anti-ulcer effect that could be related to a direct antagonism of this drug to the histamine-induced increase in gastric acid secretion and microvascular permeability (Green, 1972;Lundell & Svensson, 1974).…”

Section: Discussionmentioning

confidence: 99%

Effects of Β‐adrenoceptor Drug Stimulation on Various Models of Gastric Ulcer in Rats

Esplugues

Lloris

Martí-Bonmatí

et al. 1982

1 Experiments were designed to evaluate the effect of the pharmacological activation of fadrenoceptors on various models of gastric ulcer in the rat.2 Pretreatment with the P-adrenoceptor stimulant drugs, isoprenaline or salbutamol, significantly inhibited stress-induced gastric ulcers. This anti-ulcer effect was abolished by propranolol but not by atenolol, suggesting that P2-adrenoceptors mediate this response.3 In the pylorus-ligation model, salbutamol inhibited lesion formation and reduced the intragastric content of hydrogen ions, histamine and pepsin although the latter was only affected with the higher dose of salbutamol.4 Salbutamol also prevented the ulcerogenic action on the gastric mucosa of an exogenously perfused artificial gastric juice, showing that the anti-ulcer effect is not necessarily dependent on acid inhibition. 5 Salbutamol also reduced the formation of acute ulcers induced by various iatrogenic means (histamine, polymyxin B, reserpine and indomethacin). 6 Long-term treatment with salbutamol accelerated the healing of experimental chronic gastric ulcer.7 In anaesthetized rats, salbutamol produced a dose-related increase in mucosal blood flow which may contribute to its mode of action.8 It is concluded that P-adrenoceptor agonists exert preventive and curative effects on gastric damage induced in the rat. This effect seems specific and mediated through P-adrenoceptor activation.

“…Each value is the mean of at least 10 determinations. bradykinin by activation of at-adrenoceptors, in contrast to the mouse paw, where both ct-and ,B-adrenoceptors appear to be involved in the anti-inflammatory effect of sympathomimetic amines (Green, 1972 (Thomas, 1956;Henson, Hartness & Brunson, 1969) or the pro-inflammatory effect of adrenaline described by Selye, Somogyi & Vegh (1968). Pretreatment with heparin greatly increased the severity of petechial haemorrhage in both control and adrenaline-injected paws.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of the Pro‐inflammatory Activity of Sympathomimetic Amines in Thermic Oedema of the Rat Paw

Green

1974

1Thermic oedema induced by heating rat paws at 46.50C was potentiated by local injection of adrenaline, noradrenaline or high doses of isoprenaline. The pro-inflammatory effect of sympathomimetic amines was antagonized by phenoxybenzamine or phentolamine but not by propranolol. 2 The subcutaneous space of heated rat paws was perfused with Tyrode solution and the perfusate collected and assayed for bradykinin, bradykininogen, kinin-forming activity and kininase activity. When adrenaline (0.5 ,g/ml) was included in the perfusion fluid, kininase activity of the perfusate was increased by 76% and free bradykinin reduced by 46%. 3 Increased vascular permeability induced by injection of bradykinin or kallikrein was reduced by adrenaline or noradrenaline, but isoprenaline had no significant effect. 4 Pretreatment with soya bean trypsin inhibitor (SBTI) or heparin did not antagonize the pro-inflammatory effect of adrenaline or thermic oedema per se.