A Peripheral Adrenoceptor-mediated Sympathetic Mechanism Can Transform Stress-induced Analgesia into Hyperalgesia

A peripheral adrenoceptor-mediated sympathetic mechanism can transform stress-induced analgesia into hyperalgesia.

BACKGROUND Stress has paradoxical effects on pain, causing stress-induced analgesia but also exacerbating pain via poorly understood mechanisms. Adrenergic neurotransmission is integral in pathways that regulate the response to both pain and stress. Hyperalgesia is often associated with enhanced adrenergic sensitivity of primary afferents, but sympathetic nervous system outflow has not been dem...

Peripheral mechanism of hyperalgesia--sensitization of nociceptors.

The peripheral mechanism of hyperalgesia is considered to be the result of nociceptor sensitization. As possible agents causing nociceptor sensitization, bradykinin, histamine, prostaglandin (PG)s, protons and nerve growth factor are evaluated with respect to their release into the injured tissue, their sensitizing potencies. Whether blocking these agents suppresses sensitization was also evalu...

Guanethidine-induced destruction of peripheral sympathetic neurons occurs by an immune-mediated mechanism.

Guanethidine, a guanidinium adrenergic neuron blocking agent, when administered chronically at high doses to newborn or adult rats, causes destruction of peripheral sympathetic neurons. Neuronal destruction is preceded by small cell infiltration of the sympathetic ganglia and is suggestive of an immunologically mediated mechanism. Immune reconstitution experiments were carried out to demonstrat...

role of dorsomedian nucleus of hypothalamus in stress-induced hyperalgesia: a possbile mechanism for anxiety-induced orofacial pain

Stress-induced analgesia.

For over 30 years, scientists have been investigating the phenomenon of pain suppression upon exposure to unconditioned or conditioned stressful stimuli, commonly known as stress-induced analgesia. These studies have revealed that individual sensitivity to stress-induced analgesia can vary greatly and that this sensitivity is coupled to many different phenotypes including the degree of opioid s...