Neurohormonal modulation of the cardiac outflow through the cardioarterial
valve in the lobster.
Neuromuscular transmission and hormonal modulation in the cardioarterial valve of the lobster, Homarus americanus.
Proctolin affects the activity of the cardiac ganglion, myocardium, and cardioarterial valves in Carcinus maenas hearts.
Despite very early observations on the anatomy and innervation of various flow-rectifying structures, such as cardioarterial (CA) and segmental lateral arterial valves of the dorsal abdominal artery (Alexandrowicz, 1932a), the control of hemolymph circulation in crustaceans has been poorly understood until recently.
In the first abdominal segment, the LAA nerves supply the LAAVs of this segment and also pass forward along the DAA to terminate on the sternal cardioarterial valve (SCA).
Stimulation of the LAAV nerve at point B in the first abdominal segment produced IJPs in the sternal cardioarterial valve in addition to the ipsilateral and contralateral LAAVs in that segment (not illustrated).
Several crustacean species are known to have a muscular cardioarterial valve at the origin of each artery at the ventricle.
The nature of the innervation of the other cardioarterial valves in not known for lobsters.
The high concentration of these peptides in the pericardial organs suggests that they may be released into the circulatory system to directly affect the heart or cardioarterial valves.
The initial increase in flow in all arteries except the hepatics must have been brought about by increases in the stroke volume of the heart, since heart rate fell [ILLUSTRATION FOR FIGURE 1 OMITTED], and might also involve differential contraction of the cardioarterial valves at the base of each arterial tree.
The cardioarterial valves of the anterolateral vessels in P.
borealis (Weimann et al., 1993) and act on the cardioarterial valves of the lobster to increase cardiac output to vessels supplying the gut; they also increase hindgut motility in P.