A PHYSIOLOGICAL SALINE FOR LEPIDOPTEROUS INSECTS - EFFECTS OF IONIC COMPOSITION ON HEART BEAT AND NEUROMUSCULAR-TRANSMISSION

Three species of Lepidoptera, Bombyx mori, Agrius convolvuli and Anthe raea yamamai were used to prepare a suitable physiological saline for maintaining heart beat and junctional potentials of somatic muscle cel ls, A variety of salines designed for Lepidoptera were reexamined, Hea rt beat in the three species could not be maintained in salines used p reviously as physiological or culture solutions for Lepidoptera, Ionic compositions were determined for physiological salines that were suit able for maintaining the normal heart beat and normal neuromuscular tr ansmission in body muscle cells, It was found that salines should cont ain 12-28 mM NaCl, 32-16 mM KCl ([Na+] + [K+] = 44) and at least 9 mM CaCl2, In the salines, stimuli to motor nerves evoke action potentials of more than 40 mV in amplitude in ventral muscle cells, The ionic co mposition of a new physiological saline for Lepidoptera is as follows: NaCl, 12-28; KCl, 32-16 ([Na+] + [K+] = 44); CaCl2, 9; NaH2PO4, 1.5; Na2HPO4, 1.5; MgCl2, 18; sucrose, 175 (mM), pH 6.5.