Question

There is a disease that in the nervous system, it shows up as a reduced firing rate in the neurons. What ion or channels could cause this and how?
In the skeletal muscle, the strength of contraction is drastically reduced What ion or protein might be responsible?
In the cardiac muscle, we witness a tendency toward tetanus. The muscle isn’t relaxing sufficiently between contractions. What ion or protein might be responsible?

Answer 1

1. A reduced firing rate in the neurons, occurs due to the calcium ion (voltage gated calcium channel) enters through the N-methyl D-aspartate (NMDA) receptor and removes the AMPA receptors from the postsynaptic membrane. The glutamate receptors releasing from the presynaptic neurons are not able to interact with the AMPA receptors due to their less availabilty on the post synaptic neurons. Thus, causes the weakening of the synaptic connections or reduced firing in the neurons.

2. In the sekeltal muscle, the reduction in the strength of contraction occurs due to the reduced neurotransmitter diffusion through the synapse causing less depolarisation to the sarcolemma, that prevents the release of the Calcium ion from the sarcoplasmic reticulum.Thus,reduced strength of contraction.

3.The cardiac muscles is not relaxing enough between contractions , that is due to the less concentration of the calcium ions in the extracellular fluid and thus unable to pumped back to the sarcoplasmic reticulum causes insufficient relaxation during contractions.