The intrinsic organization of the nucleus preopticus in the catfish, Clarias batrachus (Linn.).
The organization of magnocellular neurons of the nucleus preopticus (NPO) of the catfisch, Clarias batrachus is described with the help of Nissl and aldehyde fuchsin stains and rapid Golgi technique. The NPO consists of a bilaterally located paraventricular group (PV) on either side of the preoptic recess and a supraoptic group (SO) dorsal to the optic tract. The PV shows a vertical laminar arrangement--smaller cells located adjacent to the ependyma and larger ones farther away. On the basis of the pattern of arrangement, the PV is divisible into 4 subdivisions-1: composed of small, spindle-shaped, bipolar, vertically oriented neurons characterized with short processes; subdivision 2: formed of large multipolar neurons with dendrites extending in different directions and some processes projecting into the cerebrospinal fluid (CSF); subdivision 3: consists of larger perikarya forming the lateral margin of the PV, characteristically, the processes of these neurons extend ventrolaterally and penetrate the optic tract; subdivision 4: situated posterodorsally to the above subdivisions of the PV and shows very large neurons, generally multipolar and exhibiting processes with projections to medial (MFB) and lateral (LFB) forebrain bundles, CSF, telencephalon, and towards the caudal diencephalon and tegmentum. The SO consists of three subdivisions, also arranged progressively lateralwards in order of increasing size. Processes of the lateral-most subdivision communicate with the MFB, LFB and extend into the optic tract. The NPO of C. batrachus seems comparable with the paraventricular and supraoptic nuclei of amniotes. Further the nucleus shows a complex organization and parcellation of SO and PV. By virtue of the occurrence of processes, connectivities and interneurons, the nucleus appears to play a pivotal role in receiving and integrating a wide spectrum of information to eventually influence a variety of neuroendocrine functions.
Department of Pharmaceutical Sciences, Nagpur University, India.
N
N
Subhedar
N S
NS
Rama Krishna
P D
PD
Prasadda Rao
D000818:Animals; D007025:Anterior Hypothalamic Nucleus / Q000033:anatomy & histology*; D002397:Catfishes / Q000033:anatomy & histology*; D005260:Female; D008297:Male; D012834:Silver; D013194:Staining and Labeling
D012834:Silver