Nucleus of a cell: the largest organelle. Surrounded by a double membrane called the nuclear envelope consisting of nuclear pores. These pores regulate what goes in and out of the nucleus. A bulk of the interior of the nucleus is made up of nucleoplasm which contains chromatin and nucleoli.
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens agonist-mediated responses rather than provoking a biological response itself upon binding to a receptor.They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers.n antagonist that binds to the active site of a receptor is said to be non-competitive if the bond between the active site and the antagonist is irreversible or nearly so.
Agonists are chemical substances that mimic or enhance the effects of neurotransmitters on the receptor sites of the next cell. If the neurotransmitter was excitatory, the effect of the agonist would be to increase the inhibitory. the agonist blockst the inhibitory effect.Antagonist drugs are chemical substances that block or reduce a cell's response to the action of other neurotransmitters.If the neurotransmitter is inhibitory, the antagonist would increase the activity of the cell.ntagonist drugs are chemical substances that block or reduce a cell's response to the action of other neurotransmitters. If the neurotransmitter is inhibitory, the antagonist would increase the activity of the cell.