Neurotransmitters acting in the C1 area in the tonic and reflex control of blood pressure.

An area of the rostral ventrolateral medulla (RVL), particularly that surrounding a cluster of cells of the adrenergic C1 group (the C1 area), contains neurons that function as the classical sympathoexcitatory region of the medulla oblongata. Pharmacological evidence demonstrates that these neurons are tonically regulated by inhibitory GABAergic and possibly noradrenergic inputs and by excitatory cholinergic mechanisms. Immunocytochemical studies indicate an abundance of intrinsic cholinergic and GABAergic neurons in the C1 area. Local interneurons in RVL play a critical role in regulating resting and reflex control of arterial pressure, conceivably by an action on adrenergic neurons of the C1 group.