A comparative cluster analysis of adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry in the brains of amphibians.

The Journal of comparative neurology

PubMedID: 24549578

Pinelli C, Rastogi RK, Scandurra A, Jadhao AG, Aria M, D'Aniello B. A comparative cluster analysis of adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry in the brains of amphibians. J Comp Neurol. 2014;.
NADPH-diaphorase is a key enzyme in the synthesis of the gaseous neurotransmitter nitric oxide. We compare the distribution of NADPH-d in the brain of 4 species of hylid frogs. NADPH-d-positive fibres are present throughout much of the brain, whereas stained cell groups are distributed in well-defined regions. While most brain areas consistently show positive neurons in all species, in some areas species-specific differences occur. We analysed our data and those available for other amphibian species to build a matrix on NADPH-d brain distribution for a multivariate analysis. Brain dissimilarities were quantified using the Jaccard index in a hierarchical clustering procedure. The whole brain dendrogram was compared with that of its main subdivisions by applying Fowlkes-Mallows index for dendrograms similarity, followed by bootstrap replications and permutation test. Despite the differences in the distribution map of NADPH-d system among species, cluster analysis of data from the whole brain and hindbrain faithfully reflected the evolutionary history (framework) of amphibians. Dendrograms from secondary prosencephalon, diencephalon, mesencephalon and isthmus show some deviation from the main scheme. Thus, the present analysis supports the major evolutionary stability of the hindbrain. This paper provides evidence that NADPH-d system in main brain subdivisions should be cautiously approached for comparative purposes because specific adaptations of a single species could occur and may affect the NADPH-d distribution pattern in a brain subdivision. The minor differences in staining pattern of particular subdivisions apparently does not affect the general patterns of staining across species. J. Comp. Neurol., 2014. © 2014 Wiley Periodicals, Inc.