Characterisation of a-Adrenoceptors in the Carotid Vasculature: Possible Implications for Migraine Therapy

The endogenous catecholamines noradrenaline (norepinephrine) and adrenaline (epinephrine), which are released upon activation of the sympathetic nervous system, play essential roles in the regulation of a host of physiological responses. Cardiovascular function is tightly regulated by the autonomic nervous system, i.e. by the sympathetic and parasympathetic nervous system. Sensory nerves monitor the volume and pressure status of the heart and blood vessels, as well as the metabolic state of cardiac and systemic tissues. This information is processed by the nervous system, and impulses sent via the autonomic motor nerves modulate cardiac rate and contractility, as well as coronary and systemic vascular resistance. In addition to these direct controls over the cardiovascular system, the sympathetic nervous system innervation of the kidney influences fluid and electrolyte balance.