Computational structural biology of opioid receptors

Altered Global mRNA Expressions of Pain and Aggression Related Genes in the Blood of Children with Autism Spectrum Disorders

Autism spectrum disorder (ASD) is characterized by repetitive stereotypic behaviors, restricted interests, social withdrawal, and communication deficits. Aggression and insensitivity to pain are largely unexplained in these cases. We analyzed nine mRNA expressions of the candidate genes related to aggression and insensitivity to pain in the peripheral blood of patients with ASD. Whole blood samples were obtained from 40 autistic patients (33 boys, 7 girls) and 50 age- and sex-matched controls (37 boys and 13 girls) to isolate RNA. Gene expression was assessed by quantitative Real-Time PCR (qRT-PCR) in the Erciyes University Genome and Stem Cell Center (GENKOK). All of the gene expressions except CRHR1 and SLC6A4 were found to be statistically different between the ASD patients and controls. Gene expression also differed according to gender. Alterations in the mRNA expression patterns of the HTR1E, OPRL1, OPRM1, TACR1, PRKG1, SCN9A and DRD4 genes provide further evidence for a relevant effect of the respective candidate genes on the pathophysiology of ASD. Future studies may determine the sensitivity of these candidate markers in larger samples including further neuropsychiatric diagnosis.

Mu-Opioid receptor biased ligands: A safer and painless discovery of analgesics?

Biased activation of G-protein-coupled receptors (GPCRs) is shifting drug discovery efforts and appears promising for the development of safer drugs. The most effective analgesics to treat acute pain are agonists of the μ opioid receptor (μ-OR), a member of the GPCR superfamily. However, the analgesic use of opioid drugs, such as morphine, is hindered by adverse effects. Only a few μ-OR agonists have been reported to selectively activate the G_i over β-arrestin signaling pathway, resulting in lower gastrointestinal dysfunction and respiratory suppression. Here, we discuss the strategies that led to the development of biased μ-OR agonists, and potential areas for improvement, with an emphasis on structural aspects of the ligand-receptor recognition process.