Apparent authority can legally be found, even if actual authority has not been given. There must be some act or some knowing omission on the part of the principal-if the agent alone acts to give the third party this false impression, then the principal is not bound.
An endogenous agonist for a particular receptor is a compound naturally produced by the body that binds to and activates that receptor. For example, the endogenous agonist for serotonin receptors is serotonin, and the endogenous agonist for dopamine receptors is dopamine. Full agonists bind to and activate a receptor with the maximum response that an agonist can elicit at the receptor. One example of a drug that can act as a full agonist is isoproterenol, which mimics the action of adrenaline at Î² adrenoreceptors.
Efficacy spectrum of receptor ligands. An agonist is a chemical that binds to a receptor and activates the receptor to produce a biological response. Whereas an agonist causes an action, an antagonist blocks the action of the agonist and an inverse agonist causes an action opposite to that of the agonist.ypes of agonists [edit]. Receptors can be activated by either endogenous (such as hormones and neurotransmitters) or exogenous (such as drugs) agonists, resulting in a biological response.