The endings of both types of nerves release chemicals which act on receptors in the target organs and tissues.
The parasympathetic nerves release a chemical called acetylcholine and the receptors are called cholinergic. The sympathetic nerves release the chemical noradrenaline and their receptors are called adrenergic.These latter are divided into alpha and beta receptors, named from the first two letters of the Greek alphabet.
The drugs we are talking about block the action of noradrenaline on the beta receptors and so interfere with the function of these tissues and organs when the sympathetic nervous system is stimulated.
These drugs act to reduce the work done by the heart and can prevent the disabling, severe chest pain.
Their action does not improve the efficiency of the heart but the reduction in pain can help the sufferers to lead more comfortable and productive lives.
However, caution is needed, for those with associated heart failure may find their condition worsened.
*225/71/1*
If you like this post and would like to receive updates from this blog, please subscribe our feed.