TY  - JOUR
A1  - Bonn, M.
A1  - Schmitt, A.
A1  - Lesch, K.-P.
A1  - Van Bockstaele, E. J.
A1  - Asan, E.
T1  - Serotonergic innervation and serotonin receptor expression of NPY-producing neurons in the rat lateral and basolateral amygdaloid nuclei
JF  - Brain Structure and Function
N2  - Pharmacobehavioral studies in experimental animals, and imaging studies in humans, indicate that serotonergic transmission in the amygdala plays a key role in emotional processing, especially for anxiety-related stimuli. The lateral and basolateral amygdaloid nuclei receive a dense serotonergic innervation in all species studied to date. We investigated interrelations between serotonergic afferents and neuropeptide Y (NPY)-producing neurons, which are a subpopulation of inhibitory interneurons in the rat lateral and basolateral nuclei with particularly strong anxiolytic properties. Dual light microscopic immunolabeling showed numerous appositions of serotonergic afferents on NPY-immunoreactive somata. Using electron microscopy, direct membrane appositions and synaptic contacts between serotonin-containing axon terminals and NPY-immunoreactive cellular profiles were unequivocally established. Double in situ hybridization documented that more than 50 %, and about 30–40 % of NPY mRNA-producing neurons, co-expressed inhibitory 5-HT1A and excitatory 5-HT2C mRNA receptor subtype mRNA, respectively, in both nuclei with no gender differences. Triple in situ hybridization showed that individual NPY mRNA-producing interneurons co-express both 5-HT1A and 5-HT2C mRNAs. Co-expression of NPY and 5-HT3 mRNA was not observed. The results demonstrate that serotonergic afferents provide substantial innervation of NPY-producing neurons in the rat lateral and basolateral amygdaloid nuclei. Studies of serotonin receptor subtype co-expression indicate a differential impact of the serotonergic innervation on this small, but important, population of anxiolytic interneurons, and provide the basis for future studies of the circuitry underlying serotonergic modulation of emotional stimulus processing in the amygdala.
KW  - NPY
KW  - serotonergic system
KW  - amygdala
KW  - anxiety
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132591
VL  - 218
IS  - 2
ER  - 
TY  - JOUR
A1  - Neufang, S.
A1  - Akhrif, A.
A1  - Herrmann, C.G.
A1  - Drepper, C.
A1  - Homola, G.A.
A1  - Nowak, J.
A1  - Waider, J.
A1  - Schmitt, A.G.
A1  - Lesch, K.-P.
A1  - Romanos, M.
T1  - Serotonergic modulation of 'waiting impulsivity' is mediated by the impulsivity phenotype in humans
JF  - Translational Psychiatry
N2  - In rodents, the five-choice serial reaction time task (5-CSRTT) has been established as a reliable measure of waiting impulsivity being defined as the ability to regulate a response in anticipation of reinforcement. Key brain structures are the nucleus accumbens (NAcc) and prefrontal regions (for example, pre- and infralimbic cortex), which are, together with other transmitters, modulated by serotonin. In this functional magnetic resonance imaging study, we examined 103 healthy males while performing the 5-CSRTT measuring brain activation in humans by means of a paradigm that has been widely applied in rodents. Subjects were genotyped for the tryptophan hydroxylase-2 (TPH2; G-703T; rs4570625) variant, an enzyme specific for brain serotonin synthesis. We addressed neural activation patterns of waiting impulsivity and the interaction between the NAcc and the ventromedial prefrontal cortex (vmPFC) using dynamic causal modeling. Genetic influence was examined via interaction analyses between the TPH2 genotype (GG homozygotes vs T allele carriers) and the degree of impulsivity as measured by the 5-CSRTT. We found that the driving input of the vmPFC was reduced in highly impulsive T allele carriers (reflecting a reduced top-down control) in combination with an enhanced response in the NAcc after correct target processing (reflecting an augmented response to monetary reward). Taken together, we found a high overlap of our findings with reports from animal studies in regard to the underlying cognitive processes, the brain regions associated with waiting impulsivity and the neural interplay between the NAcc and vmPFC. Therefore, we conclude that the 5-CSRTT is a promising tool for translational studies.
KW  - Clinical Genetics
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164418
IS  - 6
ER  -