1. Intravenous injection of large amounts of colloidal dyes or other substances in order to block reticuloendothelial cells ( e.g., phagocytosis is temporarily prevented). 2. Receptor b., blocking the effect of a hormone at the cell surface. 3. Arrest of peripheral nerve conduction or transmission at autonomic synaptic junctions, autonomic receptor sites, or myoneural junctions by a drug. 4. The occupation of receptors by an antagonist so that usual agonists are relatively ineffective.
- adrenergic b. selective inhibition by a drug of the responses of effector cells to adrenergic sympathetic nerve impulses (sympatholytic) and to epinephrine and related amines (adrenolytic).
- cholinergic b. 1. inhibition by a drug of nerve impulse transmission at autonomic ganglionic synapses (ganglionic b.), at postganglionic parasympathetic effector cells ( e.g., by atropine), and at myoneural junctions (myoneural b.); 2. the inhibition of a cholinergic agent.
- ganglionic b. inhibition of nerve impulse transmission at autonomic ganglionic synapses by drugs such as nicotine or hexamethonium.
- myoneural b. inhibition of nerve impulse transmission at myoneural junctions by a drug such as curare.
- sympathetic b. interruption of transmission in sympathetic ganglia or conduction of impulses in pre- or postganglionic sympathetic nerve fibers.
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block·ade blä-'kād n
1 a) interruption of normal physiological function (as transmission of nerve impulses) of a cellular receptor, tissue, or organ
b) inhibition of a physiologically active substance (as a hormone)
2) the process of reducing the phagocytic capabilities of the reticuloendothelial system by loading it with harmless material (as India ink or lampblack) which engages its cells in phagocytosis and prevents them from reacting to new antigenic material compare BLOCKING ANTIBODY
blockade vt, block·ad·ed; block·ad·ing to subject to blockade
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block·ade (blok-ādґ) 1. receptor blockade, the blocking of the effect of a hormone or neurotransmitter at a cell-surface receptor by a pharmacologic antagonist bound to the receptor. 2. in histochemistry, a chemical reaction that by modifying certain chemical groups blocks a specific staining method. 3. regional anesthesia.Medical dictionary. 2011.