Insect central nervous system transmitter

The pharmacology of insect central nervous system transmitter receptors and their associated modulatory sites and ion channels is less thoroughly known than that of the peripheral neuromuscular systems. This is in part due to the relative inaccessibility of the central... 

Reserpine treatment retards the development of allatal competence of locust females for several weeks, but basal rates appear to be normal (32). This indicates that development of the two key enzyme systems are not dependent one on the other. Reserpine acts in vertebrate systems by depleting monoamine transmitter substances in the central nervous system (33) and has been shown to activate peptidergic neurosecretory pathways in insects (34.35. The differential response to reserpine in the locust CA suggests that part of the process of developmental maturation may be dependent on neurosecretion. 

Gamma-aminobutyric acid (GABA) is an inhibitory transmitter substance in the central nervous system of both insects and higher animals. However, there are subtle differences in the properties of the GABA-receptor complex between these two groups of animals. 

The synapses using acetylcholine (ACh) as the transmitter substance are the target for a wide variety of pesticides and therefore need a more detailed description. Acetylcholine is used as a transmitter substance in nearly all animal phyla, but at different parts of the nervous system. It is also present in single-cell animals and even in plants. Enzymes that catalyze the hydrolysis of acetylcholine, the cholinesterases, are also present in various organisms not having a nervous system. In insects and other arthropods, ACh is the transmitter of messages from sensory neurons to the central nervous system (CNS) and within the CNS, but not from motor neurons to skeletal muscles, where the transmitter is glutamate. In annelids, the excitatory transmitter for the body wall muscles is acetylcholine, as at the neuromuscular junctions in vertebrates. 

---