TY - JOUR
T1 - Neuronal and inducible nitric oxide synthase immunoreactivity following serotonin depletion
AU - Ramos, Alberto Javier
AU - Tagliaferro, Patricia
AU - López-Costa, Juan José
AU - López, Ester María
AU - Saavedra, Jorge Pecci
AU - Brusco, Alicia
PY - 2002/12/20
Y1 - 2002/12/20
N2 - Serotonin (5HT) modulates the development and plasticity of its innervation areas in the central nervous system (CNS). Astrocytic 5HT1A receptors are involved in the plastic phenomena by releasing the astroglial-derived neurotrophic factor S-100β. Several facts have demonstrated that nitric oxide (NO) and the nitric oxide synthase enzyme (NOS) may also be involved in this neuroglial interaction: (i) NO, S-100β and 5HT are involved in CNS plasticity; (ii) micromolar S-100β concentration stimulates inducible-NOS (iNOS) expression; (iii) neuronal NOS (nNOS) immunoreactive neurons are functionally and morphologically related to the serotoninergic neurons; (iv) monoamines level, including 5HT, can be modulated by NO release. We have already shown that 5HT depletion increases astroglial S-100β immunoreactivity, induces neuronal cytoskeletal alterations and produces an astroglial reaction, while once 5HT level is recovered, a sprouting phenomenon occurs [Brain Res. 883 (2000) 1-14]. To further characterize the relationship among nNOS, iNOS and 5HT we have analyzed nNOS and iNOS expression in the CNS after 5HT depletion induced by parachlorophenylalanine (PCPA) treatment. Studies were performed immediately after ending the PCPA treatment and during a recovery period of 35 days. Areas densely innervated by 5HT fibers were studied by means of nNOS and iNOS immunoreactivity as well as NADPH diaphorase (NADPHd) staining. All parameters were quantified by computer-assisted image analysis. Increased nNOS immunoreactivity in striatum and hippocampus as well as increased NADPHd reactivity in the striatum, hippocampus and parietal cortex were found after PCPA treatment. The iNOS immunoreactivity in the corpus callosum increased 14 and 35 days after the end of PCPA treatment. These findings showed that nNOS immunoreactivity and NADPHd activity increased immediately after 5HT depletion evidencing a close functional interaction between nitrergic and serotoninergic systems. However, iNOS immunoreactivity increased when 5HT levels were normalized, which could indicate one of the biological responses to S-100β release.
AB - Serotonin (5HT) modulates the development and plasticity of its innervation areas in the central nervous system (CNS). Astrocytic 5HT1A receptors are involved in the plastic phenomena by releasing the astroglial-derived neurotrophic factor S-100β. Several facts have demonstrated that nitric oxide (NO) and the nitric oxide synthase enzyme (NOS) may also be involved in this neuroglial interaction: (i) NO, S-100β and 5HT are involved in CNS plasticity; (ii) micromolar S-100β concentration stimulates inducible-NOS (iNOS) expression; (iii) neuronal NOS (nNOS) immunoreactive neurons are functionally and morphologically related to the serotoninergic neurons; (iv) monoamines level, including 5HT, can be modulated by NO release. We have already shown that 5HT depletion increases astroglial S-100β immunoreactivity, induces neuronal cytoskeletal alterations and produces an astroglial reaction, while once 5HT level is recovered, a sprouting phenomenon occurs [Brain Res. 883 (2000) 1-14]. To further characterize the relationship among nNOS, iNOS and 5HT we have analyzed nNOS and iNOS expression in the CNS after 5HT depletion induced by parachlorophenylalanine (PCPA) treatment. Studies were performed immediately after ending the PCPA treatment and during a recovery period of 35 days. Areas densely innervated by 5HT fibers were studied by means of nNOS and iNOS immunoreactivity as well as NADPH diaphorase (NADPHd) staining. All parameters were quantified by computer-assisted image analysis. Increased nNOS immunoreactivity in striatum and hippocampus as well as increased NADPHd reactivity in the striatum, hippocampus and parietal cortex were found after PCPA treatment. The iNOS immunoreactivity in the corpus callosum increased 14 and 35 days after the end of PCPA treatment. These findings showed that nNOS immunoreactivity and NADPHd activity increased immediately after 5HT depletion evidencing a close functional interaction between nitrergic and serotoninergic systems. However, iNOS immunoreactivity increased when 5HT levels were normalized, which could indicate one of the biological responses to S-100β release.
KW - NADPH-diaphorase
KW - Nitric oxide
KW - Nitric oxide synthase
KW - Parachorophenylalanine
KW - Serotonin
UR - http://www.scopus.com/inward/record.url?scp=0037146952&partnerID=8YFLogxK
U2 - 10.1016/S0006-8993(02)03489-3
DO - 10.1016/S0006-8993(02)03489-3
M3 - Article
C2 - 12468035
AN - SCOPUS:0037146952
SN - 0006-8993
VL - 958
SP - 112
EP - 121
JO - Brain Research
JF - Brain Research
IS - 1
ER -