In vitro red tide toxin effects on human bronchial smooth muscle

Terufumi Shimoda, Joseph Krzanowski, Robert Nelson, Dean F. Martin, James Polson, Robert Duncan, Richard Lockey

Research output: Contribution to journalArticle

13 Scopus citations


Airborne Ptychodiscus brevis toxin (PBTX), produced by Ptychodiscus brevis (Florida red tide), induces cough, rhinorrhea, watery eyes, and sneezing in normal individuals and wheezing in subjects with asthma. The mechanism of PBTX-induced contractile response has been investigated by the authors in vitro in dog and rat tissue. PBTX stimulates neuronal sodium channels, resulting in activation of autonomic cholinergic and adrenergic nerve endings in canine upper and lower airway smooth muscle and in rat vas deferens, respectively. This article concerns the investigation of the effect and mechanism of action of PBTX on human airways in order to determine the unique role of the toxin in the pathogenesis of asthma. PBTX elicited contractions of isolated human airway smooth muscle with a threshold concentration of 0.1 μg/ml, a peak response at 12.0 μg/ml, and an effective concentration for 50% of 1.24 μg/ml, very similar to values obtained in canine lower airways. Pharmacologic analysis demonstrated that atropine (10-6 mol/L) blocked the response to both PBTX and acetylcholine; tetrodotoxin (10-7 mol/L) blocked PBTX but not acetylcholine; and verapamil (10-5 mol/L) attenuated but neostigmine (10-8 mol/L) potentiated the response to PBTX. Other selected blockers did not affect the PBTX response. These data indicate that PBTX produces contraction of human lower airway smooth muscle via stimulation of cholinergic nerve fiber sodium channels. The concept that PBTX triggers asthma through this mechanism is strengthened by these results.

Original languageEnglish (US)
Pages (from-to)1187-1191
Number of pages5
JournalThe Journal of Allergy and Clinical Immunology
Issue number6
StatePublished - Jun 1988
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Fingerprint Dive into the research topics of 'In vitro red tide toxin effects on human bronchial smooth muscle'. Together they form a unique fingerprint.

  • Cite this

    Shimoda, T., Krzanowski, J., Nelson, R., Martin, D. F., Polson, J., Duncan, R., & Lockey, R. (1988). In vitro red tide toxin effects on human bronchial smooth muscle. The Journal of Allergy and Clinical Immunology, 81(6), 1187-1191.