DMT Pressure Myography

Pressure Myography - General

The Pressure myograph systems are used to measure the physiological function and properties of small arteries, veins and other vessels. The system also allows the study of pharmacological effects of drugs and other vasoactive compounds on small isolated vessels under near physiological conditions. Vessels retain many of their in vivo characteristics when maintained under this condition.

In pressure myography, an intact small segment of an artery or vein is mounted onto two small glass cannulas and pressurized to a suitable transmural pressure. This near physiological condition permits the investigation of intrinsic (myogenic) response which can be extrapolated to the in vivo behaviour of the entire vascular bed (autoregulation). Pharmacological agents can then be studied by adding these to the superfusate or luminal solution and both constriction and dilation can be readily measured as changes in diameter of the artery via digital video edge-detection. Since intrinsic myogenic constriction is present, the role and function of the endothelium for this phenomenon can be studied.

Specialized pressure myograph chambers accommodate the combined use with (confocal) imaging or electrophysiology equipment to measure ions such as calcium or membrane potential respectively. In another development, pressure-based culture myograph are a new tool that provide long term tissue preservation to study molecular genetic changes introduced via viral vectors, siRNA or other interventions. In this way, mechanistic and molecular physiological and pharmacological studies can be done on intact tissue under near native conditions. Overall the pressure myograph technique is a very powerful tool in the hands of the dedicated vascular physiologist and pharmacologist.

Mentioned below are a few of the established areas of investigation where pressure myograph systems are utilised. The possibilities for investigation of vascular reactivity and functions may be added through the imagination of researchers.

DMT Pressure Myograph Systems

This specialty line of myographs is mostly used to study small vessel function under near physiological conditions of pressure and flow by digital tracking of diameter and flow in time.

The products include single artery systems called myographs for diameter measurement under user controlled pressure and flow conditions. Specialty versions include confocal, freeze/fix and culture myographs. The latter are used to bring the advances of molecular biology (siRNA, Viral transduction) to the study of small vessel function.

Application studies are not limited but include vascular myogenic tone regulation, endothelial function and effects of shear, calcium imaging in the arterial wall myocytes and multi-day studies of reactivity after transduction or pharmacological treatment.

DMT pressure myograph systems can be expanded with a flowmeter or luminal drug infusion or sampling ports.

Basic properties

Small vessel function, vascular diameter
Vascular smooth muscle function
Vascular endothelium function
Wall tension & thickness measurements
Vessels isolated from animal or human
Assessment of local vascular reactivity

Vasoactive mechanisms

Endothelium: role of endothelium-derived relaxing factor (NO), prostaglandins and endothelium-derived hyperpolarizing factor (EDHF)
Smooth muscle: role of calcium and potassium and other ion channels
Perivascular and intramural nerves: role of endogenous released transmitters

Pharmacology & pharmacotherapy

Quantify the effect of treatment with e.g. ACE- inhibitors, statins, glitazones or insulin
Receptor studies, localization and characterization of receptors
Affinity and efficacy studies of vasoactive agonists and antagonists

Physiological changes