One type of photochemical reaction is the dissociation of a molecule into two fragments. Since it is the electrons that provide the bonding forces that hold atoms together into molecules, if the distribution of electrons within a molecule changes drastically, the bonding forces may also change.
Trade names: IntropinÂ®, DopastatÂ®, RevimineÂ®. Mechanistic Class: sympathomimetic, dopaminergic and Î² 1 -adrenergic agonist. Therapeutic Class: vasopressor. Mechanism of action: Dopamine is a natural catecholamine neurotransmitter and is the biological precursor to norepinephrine.It increases heart rate, cardiac contractility and blood pressure by multiple mechanisms. Dopamine causes norepinephrine release from sympathetic nerve endings.echanism of action: Dopamine is a natural catecholamine neurotransmitter and is the biological precursor to norepinephrine. It increases heart rate, cardiac contractility and blood pressure by multiple mechanisms.
The existence of multiple types of receptors for dopamine was first proposed in 1976. There are at least five subtypes of dopamine receptors, D1, D2, D3, D4, and D5. The D1 and D5 receptors are members of the D1-like family of dopamine receptors, whereas the D2, D3 and D4 receptors are members of the D2-like family.