In response to varying environmental and physiological challenges, vertebrates have
evolved complex and often overlapping systems. These systems detect changes in …

In fishes, exploitation of aerial gas exchange has evolved independently many times,
involving a variety of air-breathing organs. Indeed, air-breathing occurs in at least 49 known …

The evolutionary origins of the hypoxia-sensitive cells that trigger amniote respiratory
reflexes–carotid body glomus cells, and 'pulmonary neuroendocrine cells'(PNECs)-are …

Heteropneustes fossilis is an air-breathing teleost inhabiting environments with very poor O
2 conditions, and so it has evolved to cope with hypoxia. In the gills and respiratory air-sac …

Mudskippers are amphibious fishes living in mudflats and mangroves. These fishes hold air
in their large buccopharyngeal-opercular cavities where respiratory gas exchange takes …

Acetylcholine (Ach) is the main neurotransmitter in the neuronal cholinergic system and also
works as a signaling molecule in non-neuronal cells and tissues. The diversity of signaling …

In fish, cells containing serotonin, ACh, catecholamines, NO, H 2 S, leu-5-enkephalin, met-5-
enkephalin and neuropeptide Y are found in the gill filaments and lamellae. Serotonin …

The story of control of cardiorespiratory reflexes by peripheral chemoreceptors includes a
chapter on evolution in large part because of the work of Prof. William K. Milsom. Bill has …

Serotonergic neuroepithelial cells (NECs) in larval zebrafish are believed to be O 2
chemoreceptors. Serotonin (5-HT) within these NECs has been implicated as a …

Chemoreception in fish is critical for sensing changes in the chemical composition of the
external and internal environments and is often the first step in a cascade of events leading …