Ionotropic

An ionotropic reaction describes the action of a neurotransmitter or hormone on a neural receptor. Neurotransmitters or hormones, by their presence, activate or deactivate the ionotropic receptors to cause a depolarization (positive) or hyperpolarization (negative) reaction.

For instance, a medical example of this is how the use of the neurotransmitter noradrenaline, and its binding effect to the receptors in the heart, will cause improve cardiac output. The noradrenaline causes a positive ionotropic response in the heart because the neurotransmitter affects neural receptors.