Changes

** Type A and C peripheral nociceptors are sensitised due to inflammatory mediators released by tissue damage. This lowers the response threshold of the receptors, or a greater response to the same stimulus is produced. Both mechanisms may work in conjunction.

** Type A and C peripheral nociceptors are sensitised due to inflammatory mediators released by tissue damage. This lowers the response threshold of the receptors, or a greater response to the same stimulus is produced. Both mechanisms may work in conjunction.

* Centrally, giving '''central sensitisation'''.

* Centrally, giving '''central sensitisation'''.

** The exictability of spinal nociceptive neurons is enhanced, giving a hypersensitive and hyperactice nociceptive transmission system.

** The excitability of spinal nociceptive neurons is enhanced, giving a hypersensitive and hyperactive nociceptive transmission system.

** Central sensitisation may be short-lived when it is associated with transient changes in neurotransmitter activity.

** Central sensitisation may be short-lived when it is associated with transient changes in neurotransmitter activity.

** Central sensitisation may be long-lived when it is associated with phenotypic changes in central neurons.

** Central sensitisation may be long-lived when it is associated with phenotypic changes in central neurons.

===Metabolic Effects===

===Metabolic Effects===

Pain may activate the stress response and hence hormone secretion from the pituitary glands, adrenal glands and pancreas. This leads to substrate mobilisation and catabolism, particularly protein wasting. These effects can impair wound healing, and in the long term result in immunosupression. They can also cause a negative energy balance, giving weight loss or poor growth in young animals. It is important to bear this fact in mind when considering the economics of analgesia in food animal production.

Pain may activate the stress response and hence hormone secretion from the pituitary glands, adrenal glands and pancreas. This leads to substrate mobilisation and catabolism, particularly protein wasting. These effects can impair wound healing, and in the long term result in immunosuppression. They can also cause a negative energy balance, giving weight loss or poor growth in young animals. It is important to bear this fact in mind when considering the economics of analgesia in food animal production.

===Cardiovascular Effects===

===Cardiovascular Effects===

[[Category:Anaesthesia]]

[[Category:Anaesthesia]]