Nitric oxide modulates the hyperalgesic response to mechanical noxious stimuli in sleep-deprived rats.

Background: Sleep restriction alters pain perception in animals and humans, and many studies have indicated that paradoxical sleep deprivation (PSD) promotes hyperalgesia. The hyperalgesia observed after mechanical nociceptive stimulus is reversed through nitric oxide synthase (NOS) inhibition. Both nitric oxide (NO) and the dorsolateral periaqueductal gray matter (dlPAG) area of the brainstem are involved in hyperalgesia.

Increased pain perception and attenuated opioid antinociception in paradoxical sleep-deprived rats are associated with reduced tyrosine hydroxylase staining in the periaqueductal gray matter and are reversed by L-dopa.

Paradoxical sleep deprivation (PSD) increases pain sensitivity and reduces morphine antinociception. Because dopaminergic neurons in the periaqueductal gray matter (PAG) participate in pain modulation and opioid-induced antinociception, we evaluated the effects of PSD on thermal pain sensitivity, morphine- and L-DOPA-induced antinociception and dopaminergic functionality in the PAG by assessing tyrosine hydroxylase (TH) immunoreactivity. Rats that were subjected to 96h of PSD received vehicle, morphine (2.

Systemic amitriptyline administration does not prevent the increased thermal response induced by paradoxical sleep deprivation.

Sleep deprivation has been associated with hyperalgesia in humans and in animal models. The tricyclic antidepressant amitriptyline is used as an analgesic drug in patients and in animal models of chronic pain, including that associated with spinal nerve injury. Pain hypersensitivity following paradoxical sleep deprivation (PSD) and that following peripheral nerve injury seem to share common spinal mechanisms.

Sleep deprivation affects sexual behavior and tyrosine hydroxylase (TH) levels in sexually experienced male rats.

Paradoxical sleep deprivation (PSD) produces alterations in dopaminergic systems and also modifies sexual behavior. In this work we evaluated PSD effects on the sexual response and tyrosine hydroxylase (TH) expression in dopaminergic pathways related to sexual behavior of naive and sexual experienced rats. Male Wistar rats had their sexual behavior evaluated in 6 copulatory tests, with a 4 days interval.