Effect of melatonin and pinealectomy on gonadal activity during prespawning period of catfish (Heteropneustes fossilis)

Aim: The effects of intraperitoneal administration of melatonin dose (25, 50, 100, 200 and 400 mg per fish) on gonadal activities were evaluated during the prespawning period of catfish, Heteropneustes fossilis for 60 days. Methodology: In this experiment, fourteen aquariums were used because the experiment was performed in replicate and fifteen fishes were suspended in each glass aquarium. One group of male and female catfishes were considered as control group and the catfishes in the second group were pinealectomized whereas the remaining five treatments were administered with low (25, 50 mg per fish) and high (100, 200, 400 mg per fish) doses of melatonin. Results: During prespawning period of reproductive cycle, the gonado-somatic index of ovary of pinealectomized and melatonin treated fish decreased as compared to the control group. The number of yolky oocytes significantly decreased in the melatonin treated group as compared to the control group. After 60 days of pinealectomy, it showed inhibitory effects on the ovarian activity. The GSI of testes of pinealectomized fish decreased as compared to the control group. The number of spermatozoa cells increased with the increase in the melatonin dose as compared to control group. The GSI of testes was found maximum in the melatonin treated group as compared to the control group. Interpretation: This study supports the concept that melatonin hormone administration helps in maturation of testes and increases the number of spermatozoa. This was just contrary to the results obtained in female catfish where melatonin treatment showed inhibitory effects on the ovarian activity during prespawning period.

Effect of pinealectomy and gonadectomy on dopaminergic neurons of mesencephalon in Parkinson's disease model rats / 中华行为医学与脑科学杂志

Objective To investigate the effect of PX and GDX on dopaminergic neurons of mesencephalon in Parkinson's disease model rats.Methods Eighty male Wistar rats were randomly divided into five groups:NS,N+6-OHDA,PX+6-OHDA,GDX+6-OHDA and PX+GDX+6-OHDA group;16 rats in each group.60 days after operation,6-OHDA was injected into SNc and VTA in the right side of the mesencephalon.Mter 14 days,the rats were sacrificed.HE staining was used to observe the proliferation of glial cells.The number of astrocytes was observed by GFAP staining.The number of apoptotic cells was observed by TUNEL staining.Immunohistochemical staining (S-P Method) was used to detect the changes of TH-positive cells and fiber,apoptosis-related proteins Bax and Bcl2.Results (1) The numbers of proliferated glial cells in SNc and VTA were significantly increased according to the following sequence:NS,N+6-OHDA,PX + 6-OHDA,GDX+ 6-OHDA,and PX+GDX+6-OHDA (HE staining:Hc =280.178,P＜0.01;Hc =334.260,P＜0.01) (GFAP staining:Hc=367.081,P＜0.01;Hc=376.049,P＜0.01).(2) The numbers of apoptotic cells in SNc and VTA were significantly increased according to the following sequence:NS,N+ 6-OHDA,PX+ 6-OHDA,GDX+6-OHDA,and PX+GDX+6-OHDA (Hc =344.401,P＜0.01;Hc =326.198,P＜0.01).(3) The numbers of TH (+) cells in SNc and VTA were significantly decreased according to the following sequence:NS,N+6-OHDA,PX+ 6-OHDA,GDX+ 6-OHDA,and PX+GDX+ 6-OHDA (Hc =366.532,P＜ 0.01;Hc =372.565,P＜0.01).(4) The gray values of TH(+) positive cells and fiber in SNc and VTA were significantly increased according to the following sequence:NS,N+6-OHDA,PX+6-OHDA,GDX+6-OHDA and PX+GDX+ 6-OHDA (F=517.239,P＜ 0.01;F=526.758,P＜ 0.01).(5) Bax expression:weakly positive in NS group,positive in N+6-OHDA group,and strongly positive in remaining three groups;Bcl2 expression:weakly positive in each group.Conclusion PX and GDX significantly aggravate neurotoxicity of 6-OHDA.And GDX is greater than PX,while PX + GDX is strongest.

Effect of pinealectomy and gonadectomy on dopaminergic neurons of mesencephalon in Parkinson's disease model rats / 中华行为医学与脑科学杂志

Objective To investigate the effect of PX and GDX on dopaminergic neurons of mesencephalon in Parkinson's disease model rats.Methods Eighty male Wistar rats were randomly divided into five groups:NS,N+6-OHDA,PX+6-OHDA,GDX+6-OHDA and PX+GDX+6-OHDA group;16 rats in each group.60 days after operation,6-OHDA was injected into SNc and VTA in the right side of the mesencephalon.Mter 14 days,the rats were sacrificed.HE staining was used to observe the proliferation of glial cells.The number of astrocytes was observed by GFAP staining.The number of apoptotic cells was observed by TUNEL staining.Immunohistochemical staining (S-P Method) was used to detect the changes of TH-positive cells and fiber,apoptosis-related proteins Bax and Bcl2.Results (1) The numbers of proliferated glial cells in SNc and VTA were significantly increased according to the following sequence:NS,N+6-OHDA,PX + 6-OHDA,GDX+ 6-OHDA,and PX+GDX+6-OHDA (HE staining:Hc =280.178,P＜0.01;Hc =334.260,P＜0.01) (GFAP staining:Hc=367.081,P＜0.01;Hc=376.049,P＜0.01).(2) The numbers of apoptotic cells in SNc and VTA were significantly increased according to the following sequence:NS,N+ 6-OHDA,PX+ 6-OHDA,GDX+6-OHDA,and PX+GDX+6-OHDA (Hc =344.401,P＜0.01;Hc =326.198,P＜0.01).(3) The numbers of TH (+) cells in SNc and VTA were significantly decreased according to the following sequence:NS,N+6-OHDA,PX+ 6-OHDA,GDX+ 6-OHDA,and PX+GDX+ 6-OHDA (Hc =366.532,P＜ 0.01;Hc =372.565,P＜0.01).(4) The gray values of TH(+) positive cells and fiber in SNc and VTA were significantly increased according to the following sequence:NS,N+6-OHDA,PX+6-OHDA,GDX+6-OHDA and PX+GDX+ 6-OHDA (F=517.239,P＜ 0.01;F=526.758,P＜ 0.01).(5) Bax expression:weakly positive in NS group,positive in N+6-OHDA group,and strongly positive in remaining three groups;Bcl2 expression:weakly positive in each group.Conclusion PX and GDX significantly aggravate neurotoxicity of 6-OHDA.And GDX is greater than PX,while PX + GDX is strongest.

Controladores del tiempo y el envejecimiento: núcleo supraquiasmático y glándula pineal / Aging process entrainment: suprachiasmatic nucleus and pineal gland

El núcleo supraquiasmático (NSQ) es el principal reloj biológico de los mamíferos y sincroniza la actividad de la glándula pineal al ciclo luz-oscuridad a través de una vía polisináptica. El efecto de asa de retroalimentación neuroendocrina se lleva a cabo por la melatonina. El presente trabajo pretende demostrar que la glándula pineal modula la sensibilidad a la luz en el NSQ. Se utilizaron ratas Wistar, y se asignaron a 3 grupos: grupo A (falsa pinealectomía -sham-, sin luz), grupo B (falsa pinealectomía -sham- + luz) y grupo C al cual se le realizó la pinealectomía + luz, después de la manipulación se sacrifican para realizar inmunohistoquímica para c-Fos y al final conteo celular por técnica de estereología. Se obtuvo una reducción del 46,8% del promedio de células inmunorreactivas a c-Fos en el grupo C en comparación del grupo B. Este trabajo muestra que la sensibilidad a la luz está modulada por la actividad de la glándula pineal.

The suprachiasmatic nucleus (SCN) is the main and major biological clock in mammals and is responsible for the synchronization of the pineal gland to the light/darkness cycle through a polysynaptic pathway. The neuroendocrine feedback loop effect is carried out by melatonin. This study was carried out to demonstrate that the pineal gland adjusts the sensibility to light in the suprachiasmatic nucleus. Wistar rats were allocated in 3 groups: Group A (sham pinalectomy, without light), group B (sham pinealectomy + light) and group C which underwent real pinalectomy + light. After the intervention the animals were slain to perform immunohistochemistry for c-Fos and cell counting by stereology technique. A 46.8% average reduction in c-Fos immunoreactive cells was achieved in-group C as compared with group B. The present work shows that sensibility to the light is modulate by the activity of the pineal gland.

Effect of photoperiod and melatonin on volume and cellular parameters of testis in pinealectomized rats / Efecto del fotoperiodo y la melatonina sobre el volumen y parámetros celulares de los testículos en ratas pinealectomizadas

Mammalian reproductive axis is regulated by the combination of three fundamental tissues of neuroendocrine system including hypothalamus, hypophysis and gonads. In recent years, pineal gland has been included in this axis. The aim of the present study was to investigate the effect of 12L (Light):12D (Dark) photoperiod and melatonin administration (0.5 mg/kg/day; subcutaneously) on testicular volume and cellular parameters of testis at the pinealectomized (PE) rats. For this aim, twelve adult rats were firstly pinealectomized and then divided into two groups as GI and GII randomly. The GI rats served as control group and received only normal saline, whereas GII rats were the melatonin administered group. It was found that the total testicular volume, diameter and epithelial height of seminiferous tubules and number and nuclear diameter of the interstitial cells of the testes were increased in the GII. However, increase in the interstitial cell number was not found statistically significant among groups. In conclusion, it was observed that the 12L:12D photoperiod and doses of melatonin given increased the investigated parameters in PE rats.

El eje reproductivo de los mamíferos está regulado por la combinación de tres tejidos fundamentales del sistema neuroendocrino, incluyendo el hipotálamo, hipófisis y las gónadas. En los últimos años, la glándula pineal se ha incluido en este eje. El objetivo fue investigar el efecto del fotoperíodo 12L (Luz):12O (oscuridad) y la administración de melatonina (0,5 mg/kg/día, vía subcutánea) sobre el volumen testicular y los parámetros celulares del testículo en ratas pinealectomizadas (RP). Doce ratas adultas fueron pinealectomizadas y divididas en dos grupos, GI y GII de manera aleatoria. Las ratas del GI sirvieron como grupo de control y recibieron sólo solución salina normal, mientras que a las ratas del GII se les administró melatonina. Se encontró que el volumen total, diámetro y altura del epitelio de los túbulos seminíferos de los testículos, y el número y diámetro nuclear de las células intersticiales se incrementaron en el GII. Sin embargo, el aumento en el número de las células intersticiales no fue significativo entre los grupos. En conclusión, se observó que el fotoperíodo 12L:12O y la dosis administrada de melatonina aumentan los parámetros investigados en RP.

Effect of aerobic physical exercise in pinealectomized animals submitted to the pilocarpine model of epilepsy

OBJECTIVE: To better clarify the positive effects of physical exercise in the epilepsy, we analyzed the effect of the pinealectomy in animals with temporal lobe epilepsy (TLE) induced by pilocarpine submitted to an aerobic physical program. MATERIAL AND METHODS: Forty adults Wistar rats were used: 1) PX + CHRONIC - Pinealectomized animals (PX) with TLE (CHRONIC) without exercise (n = 9); 2) PX + CHRONIC + EXERCISE - submitted to an aerobic physical exercise program (n = 5); 3) CHRONIC - without exercise (n = 8); 4) CHRONIC + EXERCISE (n = 8); 5) CTRL - control without exercise (n = 5); 6) CTRL + EXERCISE (n = 5). The physical exercise program consisted of 1 hour of treadmill, 5 days/week, during 30 days, at 60 percent VO2max. The Nissl and neo-Timm methods were used. RESULTS: The pinealectomy increased the frequency of seizures in animals with epilepsy. It was observed a reduction of the neuronal death and mossy fiber sprouting in the animals with epilepsy submitted to an aerobic physical exercise program. However, the physical exercise program did not modify the frequency of the seizures in the pinealectomized animals.

OBJETIVO: Buscando elucidar os efeitos positivos do exercício físico aeróbio na epilepsia, analisamos a influên-cia da pinealectomia em animais com epilepsia do lobo temporal (ELT) induzida por pilocarpina e submetidos a um programa de exercício físico. MATERIAL E MÉTODOS: Quarenta ratos Wistar adultos foram usados: 1) PX + CRÕNICO - pinealectomizados (PX) com ELT (CRÕNICO) sem exercício (n = 9); 2) PX + CRÕNICO + EXERCíCIO - submetidos a um programa de exercício físico aeróbio (n = 5); 3) CRÕNICO - sem exercício (n = 8); 4) CRÕNICO + EXERCíCIO (n = 8); 5) CTRL - controle sem epilepsia, sem exercício (n = 5); 6) CTRL + EXERCíCIO (n = 5). O programa de exercício físico consistiu de corrida em esteira, 5 dias/semana (30 dias) a 60 por cento VO2max. Os métodos de Nissl e neo-Timm foram utilizados. RESULTADOS: A pinealectomia aumentou a freqüência de crises em animais com epilepsia. Foi observada uma diminuição da morte neuronal e do brotamento de fibras musgosas em animais com epilepsia, submetidos ao programa de exercício físico. Entretanto, este programa não alterou a freqüência de crises em animais pinealectomizados.

Effects of ovariectomy and pinealectomy on apoptosis of cingulated gyrus cell in rats / 中华内分泌代谢杂志

The effects of ovariectomy (OVX) an d pinealectomy (PX) on apoptosis of cingulated gyrus cell in rats were investiga ted. The results suggest that OVX or PX could induce apoptosis in cingulated gyr us cells, the effect by PX is more serious than that by OVX, and combining effec t of 2 operations is more serious than either effect alone. The effects of OVX a nd PX on cell apoptosis are not related to glial cells.

Do thyroid and testis modulate the effects of pineal and melatonin on haemopoietic variables in Clarias batrachus.

Involvement of pineal and its major hormone, melatonin, in the process of erythropoiesis in a freshwater catfish, Clarias batrachus has been investigated. The study was conducted during four phases, namely preparatory phase, spawning phase, postspawning phase and late postspawning phase of its annual reproductive cycle. During each phase a fish received either melatonin injections or subjected to pinealectomy. In addition, each fish in all the groups, received either iopanoic acid or cyproterone acetate or vehicle in the morning or late afternoon. Results clearly indicate that melatonin stimulates the rate of erythropoiesis in Clarias batrachus. It appears that the extent of stimulation depends upon the phase of the annual reproductive cycle. However, in general, the pineal- or melatonin-induced modulation of blood variables is gonad dependent and thyroid seems to play a time of the day dependent subtle role.

Effects of pineal melatonin on chemiluminescence of peritoneal macrophages and PGE_2 content in the hypothalamus and spleen in rats / 中国药理学通报

Pinealectomy (PX), zymosan-in-duced-luminol-dependent-chemiluminescence (CL) and PGE2 radioimmunoassay were used to determine the effects of the pineal gland and melatonin ( MT ) on CL of peritoneal macrophages (PM?s) and PGE2 content in the hypothalamus and spleen in rats. It was suggested that the CL value of PM?s was decreased and PGE2 contents in the hypothalamus and spleenwere increased significantly after PX, which could be restored respectively by 10~ 1 000 ?g? kg-1MT and 10 ?g?kg-1MT. 10 ?g?kg-1MT could also inhibit PGE2 in the hypothalamus and spleen in normal rats.

Effect of Pinealectomy on the Renin-Angiotensin System in Sprague-Dawley Rats

Experiments were performed to investigate the effects of pinealectomy on the renin-angiotensin system in Sprague-Dawley rats. The results obtained were as follows. 1) There was no differences of systolic blood pressure, heart rate, water intake, and plasma electrolytes between pinealectomized and sham-operated rats. 2) Renin activity in plasma and pituitary gland did not differ in two experimental groups. 3) The pituitary gland contained the renin activity of about 50pg AI/hr/mg of wet weight. The results suggest that the pineal gland has no correlation with cardiovascular and renin-angiotensin system.

EFFECT OF PINEAL GLAND AND MELATONIN ON THE DEAD SIGNAL PATH OF THYMOCYTE IN RAT / 解剖学报

Objective To investigate the effect of pinealectomy and melatonin on the dead signal path of thymocyte in rat. Methods SD rats were divided into 5 groups:normal control,sham-operated control,pinealectomy,pinealectomy+melatonin injection 7.5 mg/(kg\5d);and pinealectomy+melatonin injection 15 mg/(kg\5d).The animals were sacrificed at 4 or 8 weeks after operation.Fas/FasL\,caspase-8\,caspase-12 positive cells in thymus were stained with immunocytochemical ABC method,measured by compute image analysis.The TNF-? expression in thymocyte which was influenced by melatonin was tested by RT-PCR.(Results The) area of Fas positive cells in cortex was increased significantly at 4 weeks after Px,furthermore,this trend continued to enlarge 8 weeks after Px.The result of FasL staining was similar to the Fas.The area of caspase-8 positive thymic T cells increased significantly in both cortex and medulla 8 weeks after Px,but the difference showed no significance on caspase-12.Melatonin administration attenuated the effect caused by Px.The TNF-? expression in cultured rat thymocyte was decrease by melatonin administration.Conclusion Pineal gland can regulate the apoptosis of rat thymocyte by inflence the dead signal path.Rejuvenation of degenerative thymus could be observed by melatonin administration.

PINEAL GLAND AND MELATONIN INFLUENCE THE CELL CYCLE OF THYMOCYTE / 解剖学报

Objective To study the effect of pinealctomy and melatonin on the cell cycle distribution during T cell development in thymus. Methods SD rats were divided into 5 groups:normal controls,sham-operated controls,pinealectomy,pinealectomy+melatonin injection 7.5 mg/kg; and pinealectomy+melatonin injection 15 mg/kg.The animals were sacrificed at 4 or 8 weeks after operation.cycilnA +and cyclinE +T cells in thymus were dyed with immunocytochemical ABC methods, measured by computer image analysis.Cell cycle analysis was performed by flow cytometry.The expression of cyclin-dependent kinase inhibitor 1? was tested by RT-PCR method. Results The effect of pinealectomy on the expression of cyclinE was stronger than that of cycilnA. Pinealectomy promotes the synthesis of cyclinE in thymus.The percentage of G-0/G-1 phase cells was decreased and G-2/M phase cells was increased.These would be convalescente by supplement with melatonin,but the reaction to melatonin was differencet in thymus cortex and in medulla.Melatonin enhanced the expression of cyclin-dependent kinase inhibitor 1? in thymus.Conclusion Pinealectomy influences notably the T cells development in thymus.Rejuvenation of degenerative thymus could be observed by melatonin administration.