This action of InsP 3 has been studied either at the single receptor level, in single cells or in cell populations.

Enteral administration of Naloxone blocks opioid action at the intestinal receptor level, but has low systemic bioavailability due to marked hepatic first pass metabolism.

Estrogen receptor and progesterone receptor levels in the tumor tissue.

Human epidermal growth factor type 2 receptor (HER2/neu) levels in the tumor tissue.

Determination of progesterone receptors in the primary tumor is encouraged, and entry onto an appropriate adjuvant trial (if receptor levels are high) should be considered.

Antipsychotic medications act largely as dopamine antagonists, inhibiting dopamine at the receptor level, and thereby blocking the effects of the neurochemical in a dose-dependent manner.

This difference may be related to different strengths of activity at the receptor level, such as duration and strength of receptor binding.

The neuroanatomy beyond the receptor level for surface wave-detecting neuromasts has been minimally investigated.

For example, when the synergy occurs at a cellular receptor level this is termed agonism, and the substances involved are termed agonists.

T increases the heart rate and force of contraction, thus increasing cardiac output, by increasing β-adrenergic receptor levels in myocardium.