The pharmacology of insect visceral muscle

• 1.1. At least five sites-of-action must be considered in most visceral nerve-muscle preparations.
• 2.2. L-Glutamate is perhaps the excitatory neuromuscular transmitter in some organs of the viscera but not others. Proctolin is probably a neuromuscular transmitter in some organs of the viscera defined criteria for rapid chemical transmission.
• 3.3. Although 5-HT and certain catecholamines are present in insects and have a pronounced effect on visceral muscle no functional roles has been established for them.
• 4.4. Various peptides released from neuroendocrine organs probably regulate visceral muscle function. Moreover such hormonal actions seem to be mediated by cyclic AMP in some cases.
• 5.5. Recent developments in methods for detecting peptides and prospective transmitters have increased the possibility of rapid progress in insect nerve-muscle pharmacology.