In addition to taking antihistamines, take multi-vitamins to boost your immune system during allergy season. 1  Cetirizine. Also known as Zyrtec, this is the best antihistamine available. 2  Loratadine. Also known as Claritin or Talavert. 3  Diphenhydramine. Also known as Benadryl.  Chlorphenamine.
Figure 7. How neurotransmitters work, part 1. Chemicals called neurotransmitters are responsible for transmitting nerve impulses across the synapse from one nerve cell to another, or from one nerve cell to a target organ or gland.
The outside signal (in this case, adrenaline) binds to a receptor, which transmits a signal to the G protein, which transmits a signal to adenylyl cyclase, which transmits a signal by converting adenosine triphosphate to cyclic adenosine monophosphate (cAMP). cAMP is known as a second messenger.