ABSTRACT
I. Introduction 162
II. Air Ions 162
III. Conceptual Aspects of Air Ion Biological Research 162
IV. Generating a Hypothesis 168
V. Air Ions and Serotonin 169
VI. Neuroendocrine Cell Hypothesis 170 A. Proposal 170 B. Neuroendocrine Cells 170
1. Description 170 2. Function and Innervation 171
C. Neural Pathways 172 D. Summary of NEC Hypothesis 172
VII. Further Considerations 174
Acknowledgment 175
References 175
I. INTRODUCTION
"The search for pulmonary chemoreceptors in the airways and blood vessels has been long and exhaustive owing to the teleologic attractiveness of sensors that would 'taste' the blood and `smell' the air.'" This passage from The Normal Lung by J. F. Murray addresses primarily chemoreception of the respiratory gases, 02 and CO,, as a potential control point to help maintain local ventilation-perfusion ratios. However, if Murray's comment is extended, it raises a question of sensitivity to another gaseous constituent of air, the fraction that carries charge, or, is ionized.