{'fraction_non_alphanumeric': 0.05986560781918143, 'fraction_numerical': 0.0500916310323763, 'mean_word_length': 5.157894736842105, 'pattern_counts': {'":': 0, '<': 5, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Involvement of tachykinins in plasma extravasation induced by bradykinin and low pH medium in the guinea‐pig conjunctiva

1 The effect of bradykinin, capsaicin, substance P and low pH medium on plasma extravasation in the guinea‐pig conjunctiva has been studied. Evans blue dye was measured in the conjunctiva after local instillation of the agents into the conjunctival sac. 2 Bradykinin (2–50 nmol), capsaicin (20–50 nmol) and substance P (0.5‐5 nmol) caused a dose‐dependent increase in plasma extravasation with the following order of potency: substance P> bradykinin = capsaicin. The effect of capsaicin (50 nmol) and substance P (5 nmol) was abolished by the tachykinin NKX receptor antagonist, CP‐99,994 (8umolkg−1, i.v.) (P<0.01), whereas CP‐100,263 (8 umol kg−1, i.v.) the inactive enantiomer of CP‐99, 994 was without effect. CP‐99,994 inhibited by 70% (P<0.01) the effect of bradykinin. 3 The kinin B2 receptor antagonist, Hoe 140 (icatibant, 10 nmol kg−1, i.v.) abolished the response to bradykinin (50 nmol) (P<0.01), but did not affect the responses to capsaicin (50 nmol) or substance P (5 nmol). Plasma extravasation induced by low pH medium (pH 1) was abolished by CP‐99,994 (P<0.01) and by Hoe 140 (P<0.01). 4 The present findings suggest that: endogenous or exogenous tachykinins increase plasma extravasation in the guinea‐pig conjunctiva by activation of NK1 receptors; bradykinin‐induced plasma extravasation is mediated by tachykinin release from sensory nerve endings; low pH media cause plasma extravasation via release of kinins that by activation of B2 receptors release tachykinins from sensory nerve endings.