The neurotransmitters sent by the presynaptic cells are the chemical messengers that relay information to the target cells which will be either another neuron of an effector, such as a muscle cell or gland cell.
The neurotransmitters sent by the presynaptic cells are the chemical. This chemical is messengers that relay information to the target cells such as a muscle cell or gland cell. These target cells will be either another neuron of an effector.