Biological Responses to Air Ions: Is There a Role for Serotonin?
I. Introduction 152
II. Localization and Function of 5HT 152
III. Origins of the 5HT Hypothesis-Mucociliary Activity in the Trachea 153
IV. Air Ion Exposures and 5HT Metabolism 154 A. 5HT in Blood 154 B. 5HT in Brain
155 C. Exposure and Dosimetry Considerations
V. Conclusion 159
For the past 85 years scientists and other investigators have been searching for biological responses that could be produced by alterations in the electrical characteristics of the air. In this search, most interest has focused upon ionized air molecules (air ions). Hundreds of papers have been published concerning the possible influence of air ions on biological processes. Some weak influence of air ions has been reported in many of these studies and yet in a large number of other studies no influence whatsoever could be detected. Since no common thread has been identified to conceptually relate the apparently random findings in this literature, it is reasonable to doubt the hypothesis that air ions are biologically active.