What Neurotransmitter receptors activate second messengers systems.?

Neurotransmitter receptors that activate second messenger systems include G protein-coupled receptors (GPCRs) and some receptor tyrosine kinases. When a neurotransmitter binds to a GPCR, it triggers a conformational change that activates intracellular G proteins, which in turn can modulate various second messengers like cyclic AMP (cAMP) and inositol triphosphate (IP3). These second messengers then initiate a cascade of cellular responses, influencing processes such as gene expression and cell signaling. Examples include dopamine, serotonin, and norepinephrine receptors.