Investigation of the cardiovascular control of notothenioid fish (Pagothenia borchgrevinki and Trematomus bernacchii)

The location of cholinergic, adrenergic and peptidergic receptors in the heart, gills and blood vessels was investigated from sections and isolated blood vessels using immunohistochemical techniques. Fish were stressed by forcing them to swim and physiological parameters (heart rate and ventral aortic blood pressure) were measured via the indwelling cannulae. Blood samples were taken to measure haematocrit, blood haemoglobin, plasma osmolarity and plasma adrenaline.

Samples were also analyzed for catecholamines. The effects of two stressors (hypoxia and swimming) on blood flow and heart rate and the factors controlling these changes was investigated. A range of drugs was injected into the fish and their effects were monitored (dorsal and ventral blood pressure, blood pressures, heart rate, cardiac output, stroke volume and resistance to blood flow at the gills and at the systemic capillaries).