All are features of neurotransmitters except:

Ans: C (exogenous admin...) Ref: Ganong, 22nd ed, p. 85, 94Exogenous administration does have effects, for example when adrenaline (which is a neurotransmitter) is administered; it produces a number of effects like tachycardia, increase in BP etc.Mechanism of neurotransmission* Nerve endings convert electrical energy into chemical energy by means of neurotransmitters.* These neurotransmitters are stored in synaptic vesicles and released by nerve impulses into the synaptic cleft.* These neurotransmitters then act on the post synaptic membrane which results in conduction of impulse.* After their action they are rapidly removed from synaptic cleft by diffusion, metabolism or by re- uptake into the presynaptic neuron.* Exogenous administration of the neurotransmitter can also cause effects similar to its endogenous counterpart. Noradrenaline (which is a neurotransmitter) is given in shock to raise BP.