Question

How can neurotransmitters be excitatory or inhibitory?

Answer 1

Neurotransmitters are chemical messengers that transmit a signal from a neuron across the synapse to a target cell, which may be a special neuron, muscle fiber, or gland cell. Neurotransmitters are chemical substances made by the neuron specifically to transmit a message.

Complete answer:
Neurotransmitters affect neurons in one among three ways: they will be excitatory, inhibitory, or modulatory. An excitatory transmitter generates a sign called a nerve impulse within the receiving neuron. An inhibitory transmitter prevents it. Neuromodulators regulate groups of neurons.
1. Excitatory neurotransmitters have excitatory effects on the neuron. This suggests they increase the likelihood that the neuron will fire a nerve impulse .
2. Inhibitory neurotransmitters have inhibitory effects on the neuron. This suggests they decrease the likelihood that the neuron will fire an action.
3. Modulatory neurotransmitters can affect a variety of neurons at an equivalent time and influence the consequences of other chemical messengers.
Some neurotransmitters, like dopamine, counting on the receptors present, create both excitatory and inhibitory effects.
This is an excitatory neurotransmitter that's found throughout the systema nervosum . one among its many functions is muscle stimulation, including those of the digestive system and therefore the autonomic systema nervosum.

Note:
Inhibitory synaptic transmission uses a neurotransmitter called GABA. This interacts with GABA receptors, ion channels that are permeable to charged chloride ions. Thus opening of those channels makes it harder for a neuron to get a nerve impulse.