Neurotransmission (Latin: transmissio "passing, crossing" from transmitter "to send, let pass"), also called synaptic transmission, is the process by which signaling molecules called neurotransmitters are released from the terminal axon of one neuron (the presynaptic neuron), and bind to and activate receptors on the dendrites of another neuron (the postsynaptic neuron). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay A similar process occurs in retrograde neurotransmission, where the dendrites of the postsynaptic neuron release retrograde neurotransmitters (e.g., endocannabinoids) that signal through receptors that are located on the axon terminal of the presynaptic neuron, primarily at GABAergic and glutamatergic synapses. Neurotransmission is essential for the communication process between two neurons. Synaptic transmission is based on: the availability of the neurotransmitter; the release of the neurotransmitter by exocytosis; binding of the postsynaptic receptor by the neurotransmitter; the functional response of the postsynaptic cell; and subsequent removal or deactivation of the neurotransmitter. In response to a threshold action potential or graded electrical potential, a neurotransmitter is released at the presynaptic terminal. The released neurotransmitter can then move across the synapse to be detected and bind to receptors in the postsynaptic neuron. Neurotransmitter binding can affect the postsynaptic neuron in an inhibitory or excitatory manner. The binding of neurotransmitters to receptors in the postsynaptic neuron can trigger short-term changes, such as changes in membrane potential called postsynaptic potentials, or long-term changes by activating signaling cascades. Neurons form elaborate networks through which nerve impulses (action potentials) travel. Each neuron has up to 15,000 connections with other neurons. Neurons do not touch each other (except in the case of an electrical synapse across a gap junction); instead, neurons interact at tight points of contact called synapses. A neuron carries its information through an action potential. When the nerve impulse arrives at the synapse, it can cause the release of neurotransmitters, which influence another (postsynaptic) neuron. The postsynaptic neuron can receive input from many additional neurons, both excitatory and inhibitory. The excitatory and inhibitory influences are added together, and if the net effect is inhibitory, the neuron will be less likely to "fire" (i.e., generate an action potential). , and if the final effect is excitatory, the neuron will be more likely to fire. The probability that a neuron will fire depends on how far its membrane potential is from the threshold potential, the voltage at which an action potential is fired because enough voltage-gated sodium channels are activated so that the current net incoming sodium exceeds all outgoing currents. Please note: this is just an example. Get a custom paper from our expert writers now. Get a Custom Essay Excitatory inputs drive a neuron closer to threshold, while inhibitory inputs drive the neuron further from threshold. An action potential is an "all or nothing" event; neurons whose membranes have not reached the threshold will not fire, while those that do must fire. Once the action potential has initiated (traditionally in the hillock of the axon), it will propagate down the axon, leading to the release of neurotransmitters onto the synaptic button to transmit the information.