GraninSympathoadrenal: The term sympathoadrenal means "involving the adrenal medulla and sympathetic nervous system". It normally relates to increased activity of the sympathetic nervous system which acts on the adrenal medulla of the kidney to release epinephrine and norepinephrine.Chromaffin cellBeef cattle: Beef cattle are cattle raised for meat production (as distinguished from dairy cattle, used for milk production). The meat of adult cattle is known as beef.Catecholaminergic cell groups: Catecholaminergic cell groups refers to collections of neurons in the central nervous system that have been demonstrated by histochemical fluorescence to contain one of the neurotransmitters dopamine or norepinephrine. Thus, it represents the combination of dopaminergic cell groups and noradrenergic cell groups.Calcium signaling: Calcium ions are important for cellular signalling, as once they enter the cytosol of the cytoplasm they exert allosteric regulatory effects on many enzymes and proteins. Calcium can act in signal transduction resulting from activation of ion channels or as a second messenger caused by indirect signal transduction pathways such as G protein-coupled receptors.