Question

MRO1 and MRO2 have different response properties. What is this difference? Then, please speculate why it might be useful to the crayfish to have both of these types.

Answer 1

Muscle receptor organs (MRO) in the Crayfish:

In the abdominal wall of the crayfish these organs enable proprioception; there are two types of Muscle receptor organs----> MRO 1 and MRO 2

Differences:

Muscle receptor organs – type 2 ----> these are phasic which efficiently innervated by motor unit axons, more adaptable to rapid depolarization and result in faster I_Na inactivation of action potential.

Muscle receptor organs – type 1-------> these are associated with very slow tonic neurons and shows slow adaptation to motor unit axon stimulus ---> I _{K (Ca)}, associated with sodium/potassium pump.

Uses of having MRO in crayfish: Muscle receptor organs specially innervated with motor control associated with sensory perception. These are useful in identifying stimulus further regulating the synaptic transmission associated plasticity either by excitatory neurons or by inhibitory neurons.

Research use for humans: These motor neuron stimulus preparations enable to unravel the better motor unit mechanisms on single cell basis thereby further enabling neuronal sensory perception and regulation of the motor neurons, predominantly useful in identifying novel therapies against motor neuron disorders including Parkinson’s disease.