Ontogeny of calcium-binding proteins in the cingulate cortex of the guinea pig: The same onset but different developmental patterns.

This paper compared the density of calbindin D28k (CB), calretinin (CR) and parvalbumin (PV) containing neurons in prenatal, newborn and postnatal periods in the cingulate cortex (CC) of the guinea pig as an animal model. The distribution and co-distribution among calcium-binding proteins (CaBPs) was also investigated during the entire ontogeny. The study found that CB-positive neurons exhibited the highest density in the developing CC. The CC development in the prenatal period took place with a high level of CB and CR immunoreactivity and both of these proteins reached peak density during fetal life. The density of PV-positive neurons, in contrast to CB and CR-positive neurons, reached high levels postnatally. The observed changes of the CaBPs-positive neuron density in the developing CC coincide with developmental events in the guinea pig. E.g. the eyes opening moment may be preceded by elevated levels of CB and CR at E50, whereas high immunoreactivity of PV from P10 to P40 with a peak at P20 may indicate the participation of PV in enhancement of the inhibitory cortical pathway maturation.

Calcium-binding proteins expression in the septum and cingulate cortex of the adult guinea pig.

For the first time this study demonstrates the distribution pattern and expression of three neuroanatomical markers: calbindin D28k (CB), calretinin (CR) and parvalbumin (PV) in topographically connected brain regions - the septum (SE) and the cingulate cortex (CC). The co-existence among calcium-binding proteins (CaBPs) was also examined. The study was conducted on the adult guinea pig with the use of immunohistochemical and molecular biological techniques. Among the studied CaBPs, which occurred in both examined brain regions at transcript and protein levels, CB was the most expressed in the SE, while CR in the CC. CR, unlike CB and PV, showed higher immunoreactivity in the superficial layers (II-III) of the CC than in the deep ones (V-VI). Most of CB and PV-positive perikarya were detected in the deep layers of the CC. Some CC neurons contained both CB and PV, suggesting cooperation between these CaBPs in the CC. Co-localization between CB and CR in the CC was not observed.

The ontogenetic development of neurons containing calcium-binding proteins in the septum of the guinea pig: Late onset of parvalbumin immunoreactivity versus calbindin and calretinin.

The study describes the immunoreactivity of calbindin (CB), calretinin (CR) and parvalbumin (PV), their distribution pattern and the co-distribution of CB and CR as well as CB and PV in the septum of the guinea pig during development. Immunohistochemistry was conducted on embryonic (E40, E50, E60), newborn (P0) and postnatal (P5, P10, P20, P40, P100) guinea pig brains. The presence of both CB and CR was detected at E40, while PV began to be observed at E60. Immunoreactivity for CB was constant throughout ontogeny. In contrast to CR immunoreactivity, PV immunoreactivity was higher in the postnatal stages than in the prenatal and newborn stages. Double immunostaining showed that CB co-localized with CR from E40 onwards, while with PV from P5 onwards, suggesting that CB co-operates with these proteins in the guinea pig septum during different periods of ontogeny. Our results also indicate that among the studied CaBPs, CB exhibited the highest immunoreactivity during both embryonic and postnatal development.

Tyrosine hydroxylase-immunoreactivity and its relations with gonadotropin-releasing hormone and neuropeptide Y in the preoptic area of the guinea pig.

The present study examines the distribution of tyrosine hydroxylase (TH) immunoreactivity and its morphological relationships with neuropeptide Y (NPY)- and gonadoliberin (GnRH)-immunoreactive (IR) structures in the preoptic area (POA) of the male guinea pig. Tyrosine hydroxylase was expressed in relatively small population of perikarya and they were mostly observed in the periventricular preoptic nucleus and medial preoptic area. The tyrosine hydroxylase-immunoreactive (TH-IR) fibers were dispersed troughout the whole POA. The highest density of these fibers was observed in the median preoptic nucleus, however, in the periventricular preoptic nucleus and medial preoptic area they were only slightly less numerous. In the lateral preoptic area, the density of TH-IR fibers was moderate. Two morphological types of TH-IR fibers were distinguished: smooth and varicose. Double immunofluorescence staining showed that TH and GnRH overlapped in the guinea pig POA but they never coexisted in the same structures. TH-IR fibers often intersected with GnRH-IR structures and many of them touched the GnRH-IR perikarya or dendrites. NPY wchich was abundantly present in the POA only in fibers showed topographical proximity with TH-IR structures. Althoug TH-IR perikarya and fibers were often touched by NPY-IR fibers, colocalization of TH and NPY in the same structures was very rare. There was only a small population of fibers which contained both NPY and TH. In conclusion, the morphological evidence of contacts between TH- and GnRH-IR nerve structures may be the basis of catecholaminergic control of GnRH release in the preoptic area of the male guinea pig. Moreover, TH-IR neurons were conatcted by NPY-IR fibers and TH and NPY colocalized in some fibers, thus NPY may regulate catecholaminergic neurons in the POA.