Involvement of A13 dopaminergic neurons in prehensile movements but not reward in the rat.

Tyrosine hydroxylase (TH)-containing neurons of the dopamine (DA) cell group A13 are well positioned to impact known DA-related functions as their descending projections innervate target regions that regulate vigilance, sensory integration, and motor execution. Despite this connectivity, little is known regarding the functionality of A13-DA circuits. Using TH-specific loss-of-function methodology and techniques to monitor population activity in transgenic rats in vivo, we investigated the contribution of A13-DA neurons in reward and movement-related actions. Our work demonstrates a role for A13-DA neurons in grasping and handling of objects but not reward. A13-DA neurons responded strongly when animals grab and manipulate food items, whereas their inactivation or degeneration prevented animals from successfully doing so-a deficit partially attributed to a reduction in grip strength. By contrast, there was no relation between A13-DA activity and food-seeking behavior when animals were tested on a reward-based task that did not include a reaching/grasping response. Motivation for food was unaffected, as goal-directed behavior for food items was in general intact following A13 neuronal inactivation/degeneration. An anatomical investigation confirmed that A13-DA neurons project to the superior colliculus (SC) and also demonstrated a novel A13-DA projection to the reticular formation (RF). These results establish a functional role for A13-DA neurons in prehensile actions that are uncoupled from the motivational factors that contribute to the initiation of forelimb movements and help position A13-DA circuits into the functional framework regarding centrally located DA populations and their ability to coordinate movement

Characterization of milk proteins by MALDI-ToF: influence of different packaging and shelf-life

This chapter deals with the influence evaluation of different packaging on pasteurized milk samples at T=4 °C using the MALDI-Tof (Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry) technique. Examined packages have been polypaired materials (Tetra-Brik and Tetra-Rex), polyethylene terephtalate (PET) and glass. An evaluation on the protein fraction of lighted pasteurizaed milk samples at T=4 °C over a period of 9 days of preservation has been carried out to relate this parameter with milk qulality. The collected spectra show no protein degradation until the fourth day shelf-life, while at fifth day of preservation proteolysis became more evident although no evident differences between all kind of materials were found. Nevertheless different protein profiles for each packaging were obtained at eight and nine day shelf-life with the presence of several peaks related to the pronunced proteolysis. Spectra obtained show very complicated patterns in the mass range related to proteose peptones fraction mostly coming from the proteolysis of â-casein. At nine day shelf-life milk sample in glass show the the most complex protein spectra, followed by PET and Tetra-Rex and finally by Tetra-Brik. This chapter deals with the influence evaluation of different packaging on pasteurized milk samples at T=4 °C using the MALDI-Tof (Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry) technique. Examined packages have been polypaired materials (Tetra-Brik and Tetra-Rex), polyethylene terephtalate (PET) and glass. An evaluation on the protein fraction of lighted pasteurizaed milk samples at T=4 °C over a period of 9 days of preservation has been carried out to relate this parameter with milk qulality. The collected spectra show no protein degradation until the fourth day shelf-life, while at fifth day of preservation proteolysis became more evident although no evident differences between all kind of materials were found. Nevertheless different protein profiles for each packaging were obtained at eight and nine day shelf-life with the presence of several peaks related to the pronunced proteolysis. Spectra obtained show very complicated patterns in the mass range related to proteose peptones fraction mostly coming from the proteolysis of â-casein. At nine day shelf-life milk sample in glass show the the most complex protein spectra, followed by PET and Tetra-Rex and finally by Tetra-Brik