Discovery of Selective Alpha2CAdrenergic Receptor Agonists

A novel gabapentin analogue assuages neuropathic pain response in chronic sciatic nerve constriction model in rats

Gabapentin (GBP) is an established drug that has been used in the management of symptoms of neuropathy but it is associated with unwanted side effects such as sedation and motor incoordination. The goal of the study was to find out a drug with greater efficacy and safety for the treatment of neuropathic pain. Our previously synthesized GABA analogue (Gabapentsal, GPS) was tested (25-100 mg/kg, i.p) in chronic constriction injury (CCI) induced nociceptive model of static allodynia, dynamic allodynia, thermal hyperalgesia, mechanical hyperalgesia and cold allodynia in rats (Sprague Dawley). Open field and rotarod tests were performed to assess the impact of GPS on the motor performance of the animals. GBP (100 mg/kg, i.p) was used as a standard for comparison. GPS dose dependently reduced static (P <0.001) and dynamic allodynia (P <0.001), thermal hyperalgesia (P <0.001), mechanical hyperalgesia (P < 0.001) and cold allodynia (P < 0.001). In comparison to GBP, GPS failed to alter any significantly the motor performance of rats in both the open field and rotarod assays. These results suggest that GPS is effective in alleviating nociception in CCI neuropathic pain model but free from the side effect of motor discoordination seen in the treatment with GBP. In conclusion, GPS may prove to be a prospectively more effective and safer option in the management of neuropathic syndromes.

The association of an alpha2C adrenoreceptor gene polymorphism with vasomotor symptoms in African American women

OBJECTIVE

The alpha2C adrenoreceptor deletion 322-325 (ADRA2C del 322-325) polymorphism has been associated with autonomic activity and thermoregulation, which are implicated in the vasomotor symptom (VMS) mechanism. The ADRA2C del (322-325) has higher prevalence in African American women, a group known to experience more frequent and bothersome VMS. We assessed whether the ADRA2C del (322-325) genotype is associated with increased frequency of VMS in African American women.

METHODS

DNA samples from African American (N = 400) women participating in the Study of Women's Health Across the Nation (SWAN) were genotyped for the ADRA2C del (322-325) polymorphism. Longitudinal data on VMS were obtained from the SWAN repository. The relation of ADRA2C del (322-325) genotypes (deletion/deletion [D/D]; insertion/deletion [I/D]; insertion/insertion [I/I]) with VMS over the menopausal transition for up to 12 years of follow-up was examined using generalized estimating equations. Primary models considered the outcome of frequent VMS (6 or more days in the prior 2 wk vs VMS <6 d in the prior 2 wk) by stage of menopause.

RESULTS

Four hundred DNA samples from African American women were included. Seventy-five women (18.8%) were found to carry the homozygous variant allele (D/D). There was no significant difference in the trajectory of frequent VMS over the menopausal transition between women with D/D and I/I + I/D genotypes (P = 0.39).

CONCLUSIONS

In this preliminary study among African American women in SWAN, ADRA2C del (322-325) was not significantly related to self-reported VMS. Further studies are warranted to help us understand the role of the adrenergic system in the physiology of VMS to tailor medical therapy to patient needs.