Tissue baths (often called 'organ baths') and wire myographs are versatile in vitro pharmacology techniques that have long been a mainstay of pharmacology. Many important discoveries have been made using such systems in bioassays or to investigate receptor pharmacology. The key experiments to discovery EDRF (endothelium-derived relaxing factor) were made in isolated blood vessels mounted in tissue baths for measurement of smooth muscle relaxation following the release of EDRF (nitrix oxide, prostacylcin and endothelium-derived hyperpolarizing factor, 'EDHF').
Biopta offers the most advanced instrumentation on which to conduct experiments, using a wide range of tissues including blood vessels, airways, gastrointestinal tissues, genitourinary tissues (bladder, uterus, urethra, prostate) and cardiac muscle.
Biopta has numerous Panlab (Harvard Apparatus) tissue baths at its laboratories in Glasgow, UK and Maryland, USA, with experienced scientists on-hand to investigate the contractile and relaxant properties of multiple isolated tissues in each experiment. For example, multiple bronchi may be isolated from lung tissue to allow comparisons between the bronchorelaxant properties of compounds to treat asthma or COPD. The propensity of test compounds to cause vasoconstriction of coronary arteries, cardiac muscle contractility (ventricular or atrial cardiac muscle) or the nerve-mediated control of gastrointestinal contractile activity can be studied in tissue baths.
Wire myographs (often known as Mulvany myographs) are essentially miniaturised, highly sensitive versions of tissue baths, that allow the contractile and relaxant properties of incredibly small and delicate isolated blood vessel and airways to be investigated. Tissues are mounted between two stainless steel 'jaws' held in place by two ultra-thin wires; as the tissue contracts or relaxes the force is transmitted via one of the wires to a sensitive isometric force transducer, capable of detecting micro-Newton forces (see illustration below).
This means that very small arteries, such as resistance arteries (which are the site of the greatest control of peripheral vascular resistance and hence are vital to the control of organ-specific blood flow and indeed the overall vascular component of blood pressure) can be studied in vitro. The technique requires months of practice to dissect and handle tissues without causing damage and a high level of operator skill is vital; Biopta's fully trained and experienced scientists conduct such experiments on a daily basis, using numerous Danish Myotechnology wire myographs at both our UK and US facilities.
Predictive Drug Discovery Assay Services