Other Publications (1)
Articles by Mauricio DiFulvio in JoVE
Rapid Determination of the Thermal Nociceptive Threshold in Diabetic Rats Saeed Alshahrani1, Filipe Fernandez-Conti2, Amanda Araujo2, Mauricio DiFulvio1 1Department of Pharmacology and Toxicology, Wright State University, 2Human Movement Laboratory, Universidade São Judas Tadeu Here, we describe a rapid reliable and simple procedure to determine the lowest temperature at which rats or mice show nocifensive behavior, i.e. the thermal nociceptive threshold (TNT). This method applies a slowly increasing thermal stimulus allowing precise and reproducible estimation of TNTs with minimum, if any, stress to the animals.
Other articles by Mauricio DiFulvio on PubMed
MOLECULAR AND FUNCTIONAL EXPRESSION OF CATION-CHLORIDE-COTRANSPORTERS IN DORSAL ROOT GANGLION NEURONS DURING POSTNATAL MATURATION Journal of Neurophysiology. Mar, 2012 | Pubmed ID: 22457464 GABA depolarizes and excites central neurons during early development, becoming inhibitory and hyperpolarizing with maturation. This "developmental shift" occurs abruptly, reflecting a decrease in [Cl(-)](i) and a hyperpolarizing shift in Cl(-) equilibrium potential due to upregulation of the K(+)-Cl(-) cotransporter KCC2b, a neuron-specific Cl(-) extruder. In contrast, primary afferent neurons (PANs) are depolarized by GABA throughout adulthood due to expression of NKCC1, a Na(+)-K(+)-2Cl(-) cotransporter that accumulates Cl(-) above equilibrium. The GABA(A)-mediated depolarization of PANs determines presynaptic inhibition in the spinal cord, a key mechanism gating somatosensory information. Little is known about developmental changes in Cl(-) transporters expression and Cl(-) homeostasis in PANs. Whether NKCC1 is expressed in PANs of all phenotypes or if it is restricted to subpopulations (e.g. nociceptors), is debatable. Likewise, whether PANs express KCC2s is controversial. We investigated NKCC1 and K(+)-Cl(-) cotransporters expression in rat and mouse dorsal root ganglion (DRG) neurons with molecular methods. Using fluorescence imaging microscopy we measured [Cl(-)](i) in acutely-dissociated rat DRG neurons (P0-P21) loaded with N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide, classified with phenotypic markers. DRG neurons of all sizes express two NKCC1 mRNAs, one full-length and a shorter splice variant lacking exon 21. Immunolabeling with validated antibodies revealed ubiquitous expression of NKCC1 in DRG neurons irrespective of postnatal age and phenotype. As maturation progresses [Cl(-)](i )decreases gradually, persisting above equilibrium in >95% mature neurons. DRG neurons express mRNAs for KCC1, KCC3s and KCC4, but not for KCC2s. Mechanisms underlying PANs' developmental changes in Cl(-) homeostasis are discussed and compared with those of central neurons.