Serotonin fibre densities in subcortical areas: differential effects of isolated rearing and methamphetamine

• Published in: Brain research. Developmental brain research Vol. 147; no. 1; pp. 143 - 152
• Main Authors: Lehmann, Konrad, Lesting, Jörg, Polascheck, Dierk, Teuchert-Noodt, Gertraud
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.12.2003
• Subjects: Amygdala; Amygdala - cytology; Amygdala - drug effects; Amygdala - physiology; Animals; Brain - cytology; Brain - drug effects; Brain - physiology; Caudate-putamen; Central Nervous System Stimulants - toxicity; Dopamine - physiology; Female; Gerbillinae; Immunohistochemistry; Meriones unguiculatus; Methamphetamine; Methamphetamine - toxicity; Neostriatum - cytology; Neostriatum - drug effects; Neostriatum - physiology; Nerve Fibers - drug effects; Nerve Fibers - physiology; Nucleus accumbens; Nucleus Accumbens - cytology; Nucleus Accumbens - drug effects; Nucleus Accumbens - physiology; Pregnancy; Rearing condition; Serotonin; Serotonin - physiology; Social Isolation; Nucleus accumbens; Rearing condition; Development and regeneration; Serotonin; Amygdala; Methamphetamine; Caudate-putamen
• ISSN: 0165-3806
• DOI: 10.1016/S0165-3806(03)00130-5

Serotoninergic neurons interact with dopaminergic cells on all levels and are physiologically affected by both isolated rearing (IR) and a single early methamphetamine (MA) injection. We therefore checked for anatomical effects of both interventions by immunohistochemically staining serotonin fibres and assessing fibre densities in the caudate-putamen (CPu), nucleus accumbens (NAc) and amygdala of Mongolian gerbils. IR led to significantly increased 5-HT fibre densities in the dorsal part of the CPu and in the central and basolateral amygdala. No effects were seen in the ventral CPu, in the NAc and in the lateral amygdala. The early MA injection resulted in a denser 5-HT innervation in the dorsomedial and ventromedial CPu, in the NAc shell of animals reared in an enriched environment and in the NAc core of both rearing conditions, leaving the lateral CPu and the amygdala unaffected. Thus, the single pharmacological versus the environmental challenge exerts an almost complementary effect on the 5-HT innervation in different areas of the brain, which demonstrates that systemic interactions, e.g. with dopaminergic and glutamatergic afferents, must be taken into account when the seemingly uniform 5-HT projections are investigated.