An experiment was conducted on rodents to study the impact of acetylcholine tran

Question

An experiment was conducted on rodents to study the impact of acetylcholine transport on memory. Scientists tested the long- and short-term object recognition of normal mice (WT) and mice with deficient acetylcholine transport (Deficient). They also studied the short-term memory of of female mice with (sham) or without (OVX) ovaries. On the graph (next page), * indicates that the data is statistically different from control.

a.Describe the importance of acetylcholine.

b. Explain the relationship between acetylcholine production and gender.

c. According to Figure 1, what conclusions can you draw about acetylcholine transport and memory, when it comes to gender? Why might this be the case?

d. Does it appear that estrogen plays a role in the acetylcholine transport needed for short term memory? Explain.

Explanation / Answer

a)

The importance of acetylcholine is as follows:

A long and lengthy biologically signal transmitting fibers based on the simulation of external or internal stimuli is called nerve fiber or neuron. These neurons secrete intracellular chemical messengers called neurotransmitters. These neurotransmitters are of two types, namely inhibitor neurotransmitters and excitatory neurotransmitters.

For example, glutamate, nitric oxide and aspartate are comes under excitatory neurotransmitters. GABA, Glycine, dopamine and serotonin are comes under inhibitor neurotransmitters. The Nor-epinephrine and acetylcholine are comes under both. Some of them can directly bind to the chemically gated channels and some of them transmit the signals through mediation of G-protein coupled receptors and secondary messengers.

Each neuron makes many different kinds of neurotransmitters depending on the magnitude of the action potential. Neurons can release more than one neurotransmitter. The synaptic button and other neurons contact cannot make any selection of neurotransmitter release.

Acetyl choline (Ach) is a chemical substance, which acts as a neurotransmitter at both the ganglia and effector organ sites of the parasympathetic nervous system. In sympathetic nervous system, acetyl choline is the neurotransmitter at the ganglia.

The action of acetyl choline at neuromuscular junction (NMJ) is as follows:

During resting state, the muscle cell membrane is in a polarised state and the membrane is negatively charged. When the nerve is stimulated, acetylcholine (ACh) is liberated at neuromuscular junction. ACh increases the membrane permeability of Na+ and K+ ions.

Influx of sodium ions depolarizes the membrane (activation) and the membrane becomes positively charged inside. This membrane activation triggers the release of Ca2+ from the sarcoplasmic reticulum. These calcium ions bind to the troponin in the muscle filament, which causes the exposure of myosin binding sites.

Actin-myosin cross bridges are formed, actin filaments contract over the stationary myosin filaments. After the action potential ends, the Ca2+ detaches and removed by active transport into sarcoplasmic reticulum, and the muscle fiber relaxes.   

2)

(Note: question do not contains any graph):

Here, the release of acetyl choline is directly proportional to the memory. If high amount of acetyl choline is released, then that mice will have a long term memory, vice-versa. Here, the females mice, which has low secretion or transport problem ability of acetyl choline has low memory.

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