G. Lalatta Costerbosa

In situ detection of apoptosis in regressing corpus luteum of pregnant sow: Evidence of an early presence of DNA fragmentation

Luteolysis has been shown to be correlated with apoptosis in rats, sheep, and cows. In pigs, apoptosis has already been demonstrated as regards atretic follicles. The present study has been conducted to evaluate whether apoptosis occurs during corpora lutea regression in the pregnant pig and to investigate the temporal relationship between apoptosis and functional luteolysis. The apoptotic process has been studied through the research of oligonucleosome fragmentation by means of classical electrophoresis methods and by in situ detection on histological luteal sections. The latter method allows the identification of apoptosis and the localization of apoptotic cells. Pregnant sows were cloprostenol (PGF2 alpha analog) treated and ovariectomized 0, 6, 12, 24, 48, and 72 hr after treatment. Corpora lutea were utilized for progesterone and DNA extraction and in situ evaluation of apoptosis. Clear evidence of apoptosis was seen earlier with the in situ technique (6 hr for stromal tissue, 12 hr for luteal cells) than with the classical method (24 hr). Apoptosis was, however, apparent after plasma and tissue progesterone had reached basal levels. In conclusion, these results are consistent with the hypothesis that apoptosis occurs during luteolysis in pigs. Moreover, the data obtained with the in situ technique made it possible to identify signs of structural regression in stromal tissue first than in parenchymal cells. A two-stage activation of apoptosis has been discussed to explain structural changes that occur during luteolysis after cloprostenol treatment in swine corpora lutea.

Peripheral territory and neuropeptides of the trigeminal ganglion neurons centrally projecting through the oculomotor nerve demonstrated by fluorescent retrograde double-labeling combined with immunocytochemistry.

The peripheral territories of sheep trigeminal neurons which send their central process to the brainstem through the oculomotor nerve were investigated by the use of fluorescent tracers in double-labeling experiments. For this purpose Diamidino yellow (DY) injection into the oculomotor nerve was combined with Fast blue (FB) injection either into the extraocular muscles (EOMs), or the cornea, or the superior eyelid. Double-labeled DY + FB cells were found in the ophthalmic region of the trigeminal ganglion in addition to single-labeled DY or FB cells. The DY and DY + FB-labeled trigeminal cells were analysed immunocytochemically for their content of substance P (SP)-, calcitonin gene-related peptide (CGRP)-, and cholecystokinin-8 (CCK-8)-like. All single-labeled DY cells showed SP-, CGRP- or CCK-8-like immunoreactivity. Double-labeled DY + FB neurons innervating the EOMs were immunoreactive for each of the three peptides, whereas double-labeled neurons supplying the cornea were only CGRP-like positive. The findings suggest that, in the sheep, trigeminal neurons which send their process centrally through the oculomotor nerve supply the EOMs, the cornea, and the superior eyelid and contain neuropeptides which are usually associated with pain sensation.

Mesencephalic trigeminal nucleus neurons supplying the jaw closing muscles have no spinal projection: A fluorescent double-labeling study in birds and mammals

The present study deals with the possibility that the mesencephalic trigeminal nucleus (MeV) neurons that innervate the muscle spindles of the jaw closing muscles may also have collaterals projecting to the cervical spinal cord. At the same time, we reexamine the morphology of these cells and their location within the MeV.

Different intrafusal fiber composition of spindles in sheep and pig extraocular muscles.

Histochemical profiles of intrafusal fibers have been examined in muscle spindles of extraocular muscles of sheep and pig. Results show that in the sheep the intrafusal content presents, in addition to chain fibers, at least one bag1 and one bag2 fiber, whereas in the pig almost all the spindles are bag1-fiber spindles.

Expression of α-transducin, a chemoreceptive molecule, in endocrine and non-endocrine cells of the pig gastrointestinal tract

Several neural and humoral mechanisms are known to control gut functions before, during and after food ingestion and digestion. Different specialized epithelial cells, i.e. cells that form gustatory buttons distributed throughout the oral cavity, tongue, pharynx, and epiglottis are involved in taste perception. Gustatory cells are able to discriminate different gustatory stimuli: bitter, sweet, salty and sour. Monosodium glutamate and disodium guanylate represent another type of stimulus referred to as umami. Each of these stimuli can be transduced with different modalities, in such a way that gustatory substances can act on peculiar ionic channels (i.e. salty and sour) or via G-protein coupled taste receptors (TR), i.e. TR1 and TR2 (for sweet and bitter, respectively). The activation of these receptors elicits the depolarization of gustatory cells through secondary messenger pathways. The presence of cells expressing TRs, able to discriminate different types of tastes, has been described along the gastrointestinal tract (Rozengurt and Sternini 2007) and in some segments of the respiratory system (Osculati et al. 2007) of several animal species, such as mice and rats as well as in humans. The perception of sweet and bitter is based on the activation of two TR linked G-proteins, such as α-transducin and α-gustducin. The aim of the present study was to examine: 1) the presence and distribution of α-transducin in the pig gastrointestinal (GI) tract; 2) the characterization of cells expressing α-transducin; 3) the relationship between α-transducin cells and nerve fibers supplying the GI tract mucosa.

The Mesencephalic Trigeminal Nucleus of the Duck: Development and Apoptosis

The normal development of the mesencephalic trigeminal nucleus (MesV) of the white Peking duck (Anas platyrhynchos) was studied from the 9th day of incubation until hatching and during adulthood. In the early days of embryonic development, neurons are present in the posterior commissure and in the mesenchymal tissue outside the leptomeninges in addition to those in the tectal commissure (TC) and in the optic tectum. Following the internucleosomal cleavage of DNA, a massive loss of neurons in the MesV starts in the 11-day embryo and continues until the 15th day of incubation. On the 16th day, the nucleus consists of a numerically larger medial division located in the TC and a smaller lateral division within the stratum griseum periventriculare as is found in the adult animal. The programmed cell death occurring in the MesV is discussed herein and correlated with the analogous apoptotic phenomena observed in the trigeminal motor nucleus.