Nerve-muscle networks in the accessory gland tubules of a male insect: Structural and physiological properties

Abstract

The accessory gland tubules of the cockroach Leucophaea maderae, (F.) are innervated by the phallic nerves which arise from the terminal ganglion. Tubule preparations stained with methylene blue showed that a fine network of nerve fibres covers the entire surface of the tubule with putative nerve cells at various points. Muscle fibres of the tubules were arranged in an irregular lattice and appeared as flattened elipses approx 8–10 μm across and 1.5 μm in thickness. These muscles were monomyofibrillar with a poorly developed T-tubule system and a diffuse Z band. Innervation of the muscles showed abundant evidence of neurosecretomotor-type terminals. Clear evidence was also obtained for a multiterminal-type innervation. Accessory gland tubules had a basic wave-like pattern of motion in vitro which showed a wide variation in the time-course of each swing (1–50 s). A twisting and curling motion of the tubules was also recorded. Spontaneous junctional potentials were observed in accessory gland preparations isolated from the terminal ganglion. The duration for junction potential ranged between 30–140 ms. Action potentials recorded from muscles had a slower rise time and a longer duration (230–530 ms).