Persistent supersensitivity of sigma receptors develops during repeated methamphetamine treatment

Area of Science:

• Neuroscience
• Pharmacology

Background:

• Repeated methamphetamine administration can induce behavioral sensitization.
• Sigma receptors play a role in various neurological processes.

Purpose of the Study:

• To investigate functional changes in sigma receptors following chronic methamphetamine treatment.
• To determine the duration of these changes and their relationship with dopamine system activity.

Main Methods:

• Rats were treated with methamphetamine or saline for 14 days.
• Behavioral responses to the sigma receptor agonist (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) were assessed after abstinence periods.
• The effects of dopamine D2 receptor and sigma receptor antagonists were evaluated.

Main Results:

• Methamphetamine-sensitized rats exhibited augmented behavioral responses to (+)-3-PPP, including increased rearing and stereotyped behaviors.
• This supersensitivity persisted for at least one month.
• The augmented response was reversed by combined D2 dopamine and sigma receptor antagonists.

Conclusions:

• Chronic methamphetamine treatment induces persistent functional supersensitivity of sigma receptors.
• This sigma receptor supersensitivity may contribute to the activation of the dopamine system.
• These findings highlight the long-term neurobiological consequences of methamphetamine use.