Effects of dietary inositol with sucrose stimulation on chewing and swallowing motor patterns in larvae of the silkworm Bombyx mori

The effects of dietary inositol with sucrose stimulation on chewing and swallowing motor patterns in the larvae of Bombyx mori L. are investigated. Feeding activities of the larvae are significantly enhanced by a test diet containing an inositol–sucrose mixture compared with a test diet of sucrose only. Motor patterns of the mandibular closer muscle are accelerated with shorter burst durations and shorter inter‐burst intervals with the test diet of inositol–sucrose compared with sucrose. In terms of swallowing behaviours, inositol–sucrose shortens the duration of drinking. Motor patterns of the cibarial compressor muscle are accelerated with shorter burst durations and shorter inter‐burst intervals with the inositol–sucrose mixture. Peripheral interactions between inositol‐ and sucrose‐sensitive cells in the maxilla are not detected. Thus, such interactions cannot explain the positive effects of inositol on chewing and swallowing. Responses of inositol‐sensitive cells in the epipharyngeal sensillum are not affected by sucrose. These results suggest that dietary inositol can modify chewing and swallowing motor patterns when coupled with sucrose stimuli. These modifications may occur in the central neural networks involved in chewing and swallowing motor patterns but not in peripheral sensory interactions.     

The lobster shaw gene: cloning, sequence analysis and comparison to fly shaw

We cloned and sequenced the cDNA for the shaw gene, encoding a voltage-dependent potassium (K⁺) channel, from the spiny lobster, Panulirus interruptus. The deduced amino acid sequence has a high degree of homology to the Drosophila melanogaster Shaw protein. In addition, lobster Shaw has several putative sites for post-translational modifications.     

Heartbeat control in the medicinal leech: A model system for understanding the origin,coordination, and modulation of rhythmic motor patterns

We have analyzed in detail the neuronal network that generates heartbeat in the leech. Reciprocally inhibitory pairs of heart interneurons form oscillators that pace the heartbeat rhythm. Other heart interneurons coordinate these oscillators. These coordinating interneurons, along with the oscillator interneurons, form an eight-cell timing oscillator network for heartbeat. Still other interneurons, along with the oscillator interneurons, inhibit heart motor neurons, sculpting their activity into rhythmic bursts. Critical switch interneurons interface between the oscillator interneurons and the other premotor interneurons to produce two alternating coordination states of the motor neurons. The periods of the oscillator interneurons are modulated by endogenous RFamide neuropeptides. We have explored the ionic currents and graded and spike-mediated synaptic transmission that promote oscillation in the oscillator interneurons and have incorporated these data into a conductance-based computer model. This model has been of considerable predictive value and has led to new insights into how reciprocally inhibitory neurons produce oscillation. We are now in a strong position to expand this model upward, to encompass the entire heartbeat network, horizontally, to elucidate the mechanisms of FMRFamide modulation, and downward, to incorporate cellular morphology. By studying the mechanisms of motor pattern formation in the leech, using modeling studies in conjunction with parallel physiological experiments, we can contribute to a deeper understanding of how rhythmic motor acts are generated, coordinated, modulated, and reconfigured at the level of networks, cells, ionic currents, and synapses. © 1995 John Wiley & Sons, Inc.