Pharmacodynamic tolerance is associated with changes in:

Pharmacodynamic tolerance refers to a phenomenon where the body's response to a drug diminishes over time, requiring an increased dosage to achieve the same effect. This change is primarily associated with alterations in the sensitivity of the nervous system, particularly the receptors that the drug targets. As an individual continues to use a drug, these receptors can become less responsive to it, leading to decreased efficacy of the drug’s effects.

This concept is intricately linked to the way the central nervous system adapts to repeated exposure to substances. For instance, if a person frequently uses a narcotic pain reliever, the neurons within the brain that are influenced by this medication may adapt by becoming less sensitive to the drug or by reducing the number of available receptors. This would necessitate a higher dose of the medication to achieve the initial level of effect, illustrating a clear relationship between pharmacodynamic tolerance and nervous system sensitivity.

In this context, other options such as behavioral responses, drug elimination rates, and emotional reactions could be influenced by tolerance but are not the primary aspect associated with pharmacodynamic changes. Behavioral responses might adapt somewhat as tolerance develops, and drug elimination rates pertain more to pharmacokinetics than the pharmacodynamics emphasized here. Emotional reactions could be influenced indirectly, but they