<prompt> The drug that can directly release histamine from mast cells without involving antigen-antibody reaction is:d-tubocurarine,morphine,vancomycinAll of the above  <response>: HISTAMINE RELEASERS A variety of mechanical, chemical and immunological stimuli are capable of releasing histamine from mast cells. 1. Tissue damage: trauma, stings and venoms, proteolytic enzymes. 2. Antigen: antibody reaction involving IgE antibodies. 3. Polymers like dextran, polyvinyl pyrrolidone PVP. 4. Some basic drugs--tubocurarine, morphine, atropine, pentamidine, polymyxin B, vancomycin and even some antihistaminics directly release histamine without an immunological reaction. 5. Surface acting agents like Tween 80, compound 4880 etc. The primary action of these substances is release of histamine from mast cells, therefore they are called histamine liberators. They produce an anaphylactoid reaction--itching and burning sensation, flushing, uicaria, fall in BP, tachycardia, headache, colic and asthma. Most of these symptoms are controlled by a H1 antihistaminic, better still if H2 blocker is given together. Ref:- kd tripathi; pg num:-163 