Lecture 5A: Dose Response Flashcards
What is an Agent?
Any chemical, biological, or physical material capable of eliciting a biological response
What is a dose?
the amount of that agent that comes into contact with a living organism or some part of a living organism
What is a response?
The biological reaction to an agent./Change in structure or function, morbidity, or mortality.
What is exposure?
Any condition which provides an opportunity for an external environmental agent to enter the body
Exposure is “____” the body while Dose is “____” the body
Exposure is “outside” the body while Dose is “inside” the body
What is a dose-response relationship?
the relationship between the effect of a substance on a single organism or population in relation to a specific dose.
What is another word for the does-response relationship?
It is also call dose-exposure relationship
Correlative relationship between exposure and the spectrum of effects
refer to as dose–response relationship
Whatever response is selected for measurement, the relationship between the ____________ of the biological system and the __________administered.
degree of response & amount of toxicant
Features of a Dose-Response Graph
- Shows the response data to each experimentally derived dosage
- Shows the dosage or exposure concentration of the chemical of interest.
- Usually in mg/kg (ppm)
- The values are usually in log format
D/R place pharmacology on a mathematical footing while on a practical level they are essential for making estimates of:
- Potency
- Efficacy
Uses of Dose Response (D/R) curves
- Therapeutic ratios of ED50
- Can be used as tool for investigating mechanisms of drug action and structure activity relationships
In a D/R relationship the response is due to
the chemical administered.
the data that is presented in D/R relationship is similarly to the presentation
of “dose response” in pharmacology and toxicology
The dose–response relationship is based on
the knowledge that the effect is a result of a known toxic agent or agents.
In a D/R relationship , the magnitude of the response is
in fact related to the dose.
What 3 other assumptions that recur frequently in D/R relationship?
- There is a molecular target site (or sites) with which the chemical interacts to initiate the response.
- The production of a response and the degree of response are related to the concentration of the agent at the target site.
- The concentration at the site is, in turn, related to the dose administered
The existence D/R relations means there is
A quantifiable method of measuring and a precise means of expressing the toxicity
For any given dose–response relationship, a great variety of
criteria or endpoints of toxicity could be used.
The ideal criterion for a D/R relationship would be
one closely associated with the molecular events resulting from exposure to the toxicant.
Changes in enzyme levels in blood can be indicative of
tissue damage.
Types of Dose-Response Relationships
- Individual (Graded)
- Quantal (Population)
Individual Dose-Response Relationships
Shows the response of one organism to the administered dosages of a chemical.
Individual Dose-Response Relationships is characterized by
characterized by a dose-related increase in the severity of the response.
