Neural plasticity of afferent pain pathways that is induced by prolonged or repeated noxious
stimuli may contribute to activate intrinsic inhibitory mechanisms in CNS. In order to clarify …

Evidence is presented which suggests that central neural changes occur during the brief
early phase after subcutaneous formalin injection that are essential for the expression of …

Injection of a dilute solution of formalin into a rat hindpaw produces a biphasic nociceptive
response consisting of an early phase during the first 5 min after formalin injection and a …

The purpose of this study was to investigate whether placebo analgesia is mediated by the
release of beta-endorphin. In addition to subjective pain reports, we included an objective …

Subcutaneous (sc) injection of formalin induces a rapid and prolonged hyperalgesia across
widespread areas of the body. This hyperalgesic state involves a brain-to-spinal cord …

Recent studies suggest that opioids can produce analgesia through peripheral mechanisms
following inflammation of peripheral tissue. This study examined whether opioids …

Expectations for pain relief and experience/conditioning are psychological factors that
contribute to placebo analgesia, yet few studies have studied the physiological mechanisms …

Subcutaneous injection of formalin produces a biphasic profile of pain response: a transient
early phase followed by a tonic late phase. A number of studies have indicated that the …

The magnitude of offset analgesia is not altered by naloxone administration, by remifentanil
analgesia, or during opioid-induced hypersensitivity. Offset analgesia is therefore subserved …

The formalin test is an animal model of persistent pain. Although biphasic behavioral
responses to formalin injection have been well described, the significance of the biphasic …