Neurotransmitter Basics
Neurotransmitters are chemical messengers used by the nervous system to transmit signals from one neuron (nerve cell) to another across a synapse. They play crucial roles in regulating virtually all bodily functions and mental processes.
Inhibitory vs. Excitatory Neurotransmitters
Neurotransmitters can be broadly classified based on their effect on the postsynaptic neuron:
- Inhibitory Neurotransmitters: These reduce the likelihood that the neuron will fire an action potential. They essentially calm the nervous system down.
- Excitatory Neurotransmitters: These increase the likelihood that the neuron will fire an action potential. They stimulate the nervous system.
Some neurotransmitters can be both, depending on the receptor they bind to, but many have a primary role.
Analyzing the Options
Let's examine the roles of the neurotransmitters listed:
Option 1: Epinephrine
Epinephrine (also known as adrenaline) is primarily a hormone involved in the body's stress response (the "fight or flight" response). While it can act as a neurotransmitter in the brain, it's often considered excitatory or modulatory, increasing alertness and arousal.
Option 2: Glutamate
Glutamate is the most abundant neurotransmitter in the central nervous system and is the principal excitatory neurotransmitter. It plays vital roles in learning and memory but is not an inhibitory neurotransmitter.
Option 3: GABA
GABA stands for Gamma-Aminobutyric Acid. It is the chief inhibitory neurotransmitter in the mature vertebrate central nervous system. GABA works by decreasing neuronal excitability throughout the nervous system. It helps reduce anxiety, calm nerves, and promote relaxation.
Option 4: Nor epinephrine
Norepinephrine (also known as noradrenaline) is closely related to epinephrine and also plays a role in the stress response. It acts as both a hormone and a neurotransmitter, primarily involved in vigilance, arousal, and attention. It is generally considered excitatory or modulatory.
Conclusion
Based on the analysis, GABA (Gamma-Aminobutyric Acid) is the primary inhibitory neurotransmitter among the choices provided. It functions to reduce neuronal excitability.
Important Questions from Miscellaneous
A stone is thrown horizontally from the top of a 20 m high building with a speed of 12 m/s. It hits the ground at a distance R from the building. Taking g = 10 m/s2 and neglecting air resistance will give :
A mass is attached to a spring that hangs vertically. The extension produced in the spring is 6 cm on Earth. The acceleration due to gravity on the surface of the Moon is one-sixth of its value on the surface of the Earth. The extension of the spring on the Moon would be:
Directions: Each item in this section consists of a sentence with an underlined word followed by four words (a), (b), (c), and (d). Select the option that is opposite in meaning to the underlined word and mark your response in your Answer Sheet accordingly.
The deluge affected the population.The major source of vitamins and minerals for vegetarians is
Which of the following statements about the Deccan Riots Commission is/are correct?
1. The Commission did not hold enquiries in the districts which were not affected.
2. The Commission did record the statements of ryots, sahukars and eye-witnesses.
Select the correct answer using the code given below:
