Specific Pain Model

Studies employing animal models, especially those closely simulating certain clinical painful conditions, have markedly improved our knowledge of pain and its underlying mechanisms. Different models should be reported and interpreted in the context of the specific pain model. Although there may be common underlying mechanism in many chronic pain condiction sensitization different models also have their own specific underlying mechanisms. Chronic pain (including neuropathic pain) for which medical assistance is sought invariably presents with more than just allodynia and hyperalgesia, which are its principal diagnostic features [2,4–10,14,15,18,19,21–23,25].

In diferents of experiments, rats were evaluated prior to and following CCI of the sciatic

These are a series of hairs/nylon monofilaments of various thicknesses that exert various degrees of force when applied to the plantar surface of the hind paw. Responses can be quantified as percent response or duration of response to a given monofilament force applied several times, or mechanical threshold can be determined using the up-down method [32]. Nerve ligation models have served as powerful tools that not only mimic clinical symptoms of chronic neuropathic pain. For example, in humans chronic neuropathic pain is manifested through spontaneous pain that can be induced through innocuous stimuli (allodynia) [10]. Accordingly, mice and rats exposed to nerve ligation surgery display reduced mechanical thresholds, whereby previously innocuous mechanical stimuli elicit nociceptive paw withdrawal responses after surgery [11,12]. Similarly, chronic neuropathic pain patients also display exaggerated responses to noxious stimuli (hyperalgesia), and animal studies have shown similar responses following peripheral nerve injury [13]. Several tools have been devised to investigate these behavioral effects, most notably Von Frey filaments for mechanical allodynia, and the acetone test for thermal hyperalgesia. Our work demonstrates that the adaptation of the classic CCI model can be used to study neuropathic

These observations have shown coexistence between the syndrome pain-depression and separately pain and depression. Both conditions respond to a similar treatment, exacerbating other and sharing the same pathophysiological and pharmacological mechanisms (Jun-Xu Li, 2015). Pain and depression have been mutually connected in various experimental and clinical studies. Chronic pain is linked to individuals with a history of depression (Bair et al., 2005) and depression increases the painful diseases (Geisset et al., 2000).

The forced swimming test evaluates the possibility of rodents to escape from an uncomfortable situation. This test can be used in preclinical studies to measure the effectiveness of antidepressants (Porsolt et al., 2001). Based on this, Lucky et al (1997) have set up some parameters in the FST, and thus one can distinguish two types of escape behavior during the forced swim test behavior; are horizontal movements while swimming and climbing, which are vertical movements with the legs directed from the