Ptychodiscus brevis, which causes Florida red tide, produces Ptychodiscus brevis toxin (PBTX) known to contain @entity2359 and to induce @entity5254 , tearing, and cough in normal @entity1 and wheezing in asthmatic subjects. It was previously reported (J Allergy Clin Immunol 69:418, 1982; 73:824, 1984) that PBTX causes @entity235 tracheal smooth muscle contraction via stimulation of @entity1372 channels in the axons of parasympathetic postganglionic nerves and the release of @entity934 from these nerve endings. This was postulated to be an asthma-triggering mechanism. In this article the toxins were evaluated to determine if they also stimulate @entity1372 channels on adrenergic nerve endings and release @entity1063 . @entity35 @entity8050 deferens was selected as the experimental tissue. Both PBTX and @entity1063 contracted @entity35 @entity8050 deferens. @entity3159 10(-6) mol/L blocked the response to PBTX (3 micrograms/ml) (88.3% to 27.3% contraction [n = 6; p less than 0.001]) and the response to @entity1063 (EC50 was shifted from 1.67 X 10(-6) mol/L to 1.25 X 10(-4) mol/L in the presence of @entity3159 10(-6) mol/L [n = 6; p less than 0.001]). @entity5521 10(-6) mol/L also blocked both PBTX and @entity1063 . @entity1022 10(-7) mol/L, a @entity1372 channel blocker, completely blocked the response to PBTX but not to @entity1063 . The response to PBTX was significantly reduced from 1.53 gm of @entity2701 in controls to 0.29 gm of @entity2701 (n = 6; p = 0.002) in tissues obtained from @entity35 pretreated with @entity2515 (2 mg/kg per day for 2 days, injected intraperitoneally). @entity1855 10(-5) mol/L blocked the PBTX response, and PBTX caused no contraction in @entity460 -free media.(ABSTRACT TRUNCATED AT 250 WORDS)

The mechanism of Ptychodiscus brevis toxin-induced XXXX @entity8050 deferens contraction.

@entity1 :: ('9606', 'Species') :: ['humans'] @entity235 :: ('9615', 'Species') :: ['canine'] @entity3159 :: ('MESH:D011224', 'Chemical') :: ['Prazosin', 'prazosin'] @entity1022 :: ('MESH:D013779', 'Chemical') :: ['Tetrodotoxin'] @entity5521 :: ('MESH:D010646', 'Chemical') :: ['Phentolamine'] @entity1372 :: ('MESH:D012964', 'Chemical') :: ['sodium'] @entity2515 :: ('MESH:D012110', 'Chemical') :: ['reserpine'] @entity1855 :: ('MESH:D014700', 'Chemical') :: ['Verapamil'] @entity2701 :: ('MESH:D018781', 'Disease') :: ['tension'] @entity5254 :: ('MESH:D002559', 'Disease') :: ['rhinorrhea'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity35 :: ('10116', 'Species') :: ['rat', 'Rat', 'rats'] @entity1063 :: ('MESH:D009638', 'Chemical') :: ['norepinephrine'] @entity8050 :: ('24221(Tax:10116)', 'Gene') :: ['vas'] @entity2359 :: ('MESH:D020258', 'Disease') :: ['neurotoxins'] @entity934 :: ('MESH:D000109', 'Chemical') :: ['acetylcholine']
@entity35 :: (10116,Species) :: ['rat']
