Membrane Potentials, Synaptic Responses, Neuronal Circuitry, Neuromodulation and Muscle Histology Using the Crayfish: Student Laboratory Exercises

Abstract

The purpose of this report is to help develop an understanding of the effects caused by ion gradients across a biological membrane. Two aspects that influence a cell's membrane potential and which we address in these experiments are: (1) Ion concentration of K + on the outside of the membrane, and (2) the permeability of the membrane to specific ions. The crayfish abdominal extensor muscles are in groupings with some being tonic (slow) and others phasic (fast) in their biochemical and physiological phenotypes, as well as in their structure; the motor neurons that innervate these muscles are correspondingly different in functional characteristics. We use these muscles as well as the superficial, tonic abdominal flexor muscle to demonstrate properties in synaptic transmission. In addition, we introduce a sensory-CNS-motor neuron-muscle circuit to demonstrate the effect of cuticular sensory stimulation as well as the influence of neuromodulators on certain aspects of the circuit. With the techniques obtained in this exercise, one can begin to answer many questions remaining in other experimental preparations as well as in physiological applications related to medicine and health. We have demonstrated the usefulness of model invertebrate preparations to address fundamental questions pertinent to all animals.

The effects of potassium and muscle homogenate on proprioceptive responses in crayfish and crab

“…Suction electrodes made from glass pipettes fitted with plastic tips were used to record extracelluar signals from the cut nerves (details of making the suction electrodes is provided in Baierlein et al., ). A P‐15 amplifier (Grass Instruments, Astro‐Med, West Warwick, RI) in conjunction with a PowerLab/4s A/D converter and Lab Chart 7 software (ADI Instruments, Colorado Springs, CO) obtained the signals to be recorded on a computer at a 10 or 20 kHz sampling rate.…”

“…Suction electrodes made from glass pipettes fitted with plastic tips were used to record extracelluar signals from the cut nerves (details of making the suction electrodes is provided in Baierlein et al, 2011).…”

The Effect of Bacterial Endotoxin LPS on Serotonergic Modulation of Glutamatergic Synaptic Transmission

“…Suction electrodes made from plastic tips were used to stimulate the cut nerves (details of making the suction electrodes are provided in Baierlein et al [38]). The nerve was stimulated with supramaximal pulses using a suction electrode and Grass S-88 stimulator to elicit EJPs.…”

Prediction of the neuropeptidomes of members of the Astacidea (Crustacea, Decapoda) using publicly accessible transcriptome shotgun assembly (TSA) sequence data

“…Many astacideans are also commonly used laboratory animals, both for educational exercises (e.g. Baierlein et al, 2011;Cooper et al, 2011;Leksrisawat et al, 2010;Robinson et al, 2011) and for biomedical studies of neural network organization and neuromodulation (e.g. the stomatogastric and cardiac neuromuscular systems of lobsters and crayfish are among the premiere models for studying the basic principles that underlie the generation, maintenance and modulation of rhythmically active motor behaviors [e.g.…”