Effects of salts on Anopheles heart rates

Actions on Insects and Other Invertebrates

“…In the reviews of KRIJGSMAN (1952) and of KruJGSMAN and DIVARIS (1955) the conclusions reached, stated in the simplest terms, were that the arthropod heart is neurogenic and the molluscan heart, myogenic; yet a more recent analysis of the structure, physiology, and pharmacology of the insect heart alone by JoNES (1956) indicates that functionally there are at least three types of heart in this one class: neurogenic, innervated myogenic, and non-innervated myogenic. With the crustacean, Daphnia, BEKKER and KRIJGSMAN (1951) had already obtained evidence that this animal has a myogenic heart, while BEARD (1953) concluded from his extensive survey of the data on insect hearts that there was at that date no agreement as to the neurogenic or myogenic origin of the heartbeat in this group.…”

Some Observations on Cardiac Automatism in Certain Animals

“…Since no organized, localized, innervated pacemaker is apparent in the myocardium of this species, nervous intervention is precluded in the interpretation of the effects of drugs. These hearts, whether fresh or hypodynamic, are completely insensitive to acetylcholine; in this regard they closely resemble other myogenic hearts such as Fundulus (Armstrong, 1935), chick (Markowitz, 1931), and Limulus (Prosser, 1942) embryos prior to innervation as well as adult Anopheles (Jones, 1956), Artemia and Eubranchipus (Prosser, 1942). Apparently innervation and acetylcholine sensitivity are linked; if this be so, then it is quite difficult to visualize how acetylcholine can mediate automaticity in non-innervated structures, and it is concluded that this compound does not assume a role in the rhythmic activity of such tissues.…”