A new neurosecretory system in fish, located in the gill region

Abstract

850shift of a certain amount of water from the intracellular to the extracellular space. However the results obtained do not indicate whether the increase of inulin uptake due to contractile activity can be attributed to an actual change of volume of the extracellular space rather than to a modification in the diffusion kinetics of inulin: in this latter case we must assume that non equilibrium conditions are present H. During contractions, inulin might be taken up more easily by compartments (perhaps other than the extracellular space) where, Experientia 37 (1981), Birkh/iuser Verlag, Basel (Schweiz) in resting conditions, it enters at a very low rate: it seems difficult to explain why the phenomenon should be less pronounced or absent following isotonic contractions. In order to clarify the results obtained, a further investigation will be devoted to the diffusion kinetics of inulin and HTO in resting and active muscles. Anyhow the results obtained suggest that the determination of cellular electrolytes in isolated muscle preparations should be accompanied by an accurate measurement of the extracellular space and its possible changes due to the experimental conditions. Summary. A peculiar neurosecretory system is reported in 6 teleost species; Clarias batrachus, Heteropneustes fossilis, Mystus seenghala, Ompak pabda, Glassogobius giuris and Notopterus notopterus. It is located in the gill region close to the pseudobranch or to the carotid labyrinth. The neurosecretory ceils have been identified using stains specific for neurosecretion. The results are discussed in the light of the association of the neurosecretory system with the pseudobranch or the carotid labyrinth, and the airbreathing habit of these fishes.In fishes, only 2 neurosecretory systems are known; the hypophysial system of the head and the caudal neurosecretory system of the tail. A peculiar 3rd system of neurosecretion has been found by us to exist in certain fishes, and in the present report an account of this is presented. The neurosecretory cells have been identified histologically, using neurosecretory stains like aldehyde fuchsin 2, acidviolet 3 and iron-haematoxylin 4. So far, this system has been found in 6 teleostean species; namely Clarias batrachus, Heteropneustes fossilis, Mystus seenghala, Ompak pabda, Glassogobius giuris and Notopterus notopterus, which belong to 3 different orders, but not in the carps Labeo rohita and Cirrhinus mrigala. Results. In the 6 species mentioned above, neurosecretory cells are found to occur clumped into groups forming a large ganglionic mass, which is located in the gill region in

Fine structure of diffused pseudobranchial neurosecretory cells associated with carotid labyrinth in an air‐breathing catfish Clarias batrachus

“…) but it is also present in other fish species (Srivastava et al . ; Gopesh , ; Srivastava and Gopesh ; Gopesh et al . ).…”

“…Investigations on these cells have resulted in the establishment of a third neurosecretory system for fish – the pseudobranchial neurosecretory system (PNS) (Srivastava et al . ; Gopesh ; Srivastava and Gopesh ). The presence of PNS is ubiquitous in catfishes including marine ones (S. order Siluroidei; order Siluriformes) (Gopesh ; Gopesh and Srivastava ; Gopesh et al .…”

“…The PNS has been found in close proximity to the pseudobranch in Glossogobius giuris (Srivastava et al . ; Gopesh ), carotid gland in Notopterus chitala and N. Notopterus (Srivastava et al . ; Gopesh , ; Gopesh et al .…”

“…; Gopesh ), carotid gland in Notopterus chitala and N. Notopterus (Srivastava et al . ; Gopesh , ; Gopesh et al . ) and the CL in catfishes (Gopesh ; Gopesh and Srivastava ; Gopesh et al .…”

Paraneuronal pseudobranchial neurosecretory cells in scorpion catfish Heteropneustes fossilis: an environment scanning electron microscope and transmission electron microscope study

“…The pseudobranchial neurosecretory system (PNS) is the third system of neurosecretion, apart from the two well‐known neurosecretory systems already known for fishes, namely the hypopthalamo‐hypophysial system of brain and the caudal neurosecretory system of tail. The PNS enjoys the status of a diffuse neuroendocrine system in fishes (Srivastava et al. 1981; Gopesh 1983), which seems to be a part of gill neuroendocrine apparatus, contributing to the complex functions of gill viz gas exchange, ion regulation, osmoregulation, acid–base balance, ammonia excretion (Wilson and Laurent 2002; Evans et al.…”