Neurochemical Messengers: Core Concepts

Neurotransmitter Basics

• Neurotransmitters (NTs) are diverse chemical messengers, each with specific roles, functioning as excitatory, inhibitory, or both.
• NT molecules cross the synaptic gap, where their distribution and timing vary.
• NTs bind to specific receptor sites on receiving neurons, similar to a key in a keyhole.
• Other substances like drugs or venoms can mimic NTs, affecting neurotransmission.
• While most neurons secrete one NT type, a single neuron can receive multiple types simultaneously.
• NT binding at receptor sites either excites the neuron (moving it closer to firing threshold) or inhibits it (preventing firing).
• Triggering an action potential often requires the cumulative effect of multiple excitatory messages, not just one.