Genetic variation of the ghrelin signalling system in individuals with amphetamine dependence

PLoS One. 2013 Apr 8;8(4):e61242. doi: 10.1371/journal.pone.0061242. Print 2013.

Abstract

The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL) as well as GHS-R1A (GHSR) genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs) and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104) and controls from the general population (n = 310). A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI) composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (pc = 0.02). A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (pc = 0.03). The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alleles
  • Amphetamine / metabolism*
  • Amphetamine-Related Disorders / genetics*
  • Amphetamine-Related Disorders / metabolism*
  • Case-Control Studies
  • Female
  • Gene Frequency
  • Genetic Association Studies
  • Genetic Variation*
  • Ghrelin / genetics*
  • Ghrelin / metabolism
  • Haplotypes
  • Humans
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Receptors, Ghrelin / genetics
  • Signal Transduction*
  • Young Adult

Substances

  • Ghrelin
  • Receptors, Ghrelin
  • Amphetamine

Grants and funding

This study was supported by the Swedish Research Council (grant numbers 30207123, K2006-21X-04247-33-3 and 2009-2782), the Swedish National Drug Policy Coordinator (a government agency), and the Stockholm County Council. The Swedish brain foundation, LUA/ALF (grant no. 148251) from the Sahlgrenska University Hospital, Alcohol research council of the Swedish alcohol retailing monopoly and the foundations of Adlerbertska, Fredrik and Ingrid Thuring, Tore Nilsson, Längmanska, Torsten and Ragnar Söderberg, Wilhelm and Martina Lundgren, Knut and Alice Wallenberg, Magnus Bergvall, Anérs, Jeansons, Åke Wiberg, NovoNordisk and the Swedish Society of Medicine. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.