S.K. Mahata

Influence of age and splanchnic nerve on the action of melatonin in the adrenomedullary catecholamine content and blood glucose level in the avian group

SummaryA single intraperitoneal (IP) melatonin injection (0.5 mg/100 g body wt.) caused an increase in norepinephrine (NE) fluorescence and elevation of NE content in newly-hatched pigeons (Columba livia), but a reduction of NE fluorescence and depletion of NE content in the adrenal medulla of newly-hatched crows (Corvus splendens) after 0.5 h of treatment. In contrast, in adults melatonin caused increase in NE fluorescence and elevation of NE content only in the parakeet (Psittacula krameri).Half an hour of IP melatonin treatment (0.5 mg/100 g body wt.) induced release of epinephrine (E) from the adrenal medulla of newly-hatched pigeon and parakeet. In contrast, in the adults melatonin caused more than a two-fold increase in E in the pigeon, and a significant increase in the crow.Single IP melatonin injection (0.5 mg/100 g body wt.) caused hypoglycemia in the newly-hatched parakeet and adult pigeon, and hyperglycemia in newly-hatched pigeon after 0.5 h of treatment. Melatonin failed to regulate glucose homoeostasis in newly-hatched and adult crow.Splanchnic denervation of the left adrenal gland was performed in the adult pigeon. The right adrenal served as the innervated gland. Melatonin-induced modulation of catecholamines following a single IP injection (0.5 mg/100 g body wt.) revealed significant increases in NE fluorescence and NE content at 4 and 12 h after treatment in the denervated gland only, which gradually approached normal levels 9 days after treatment. In contrast, E content showed more than a two-fold increase over the control value in both the innervated and denervated glands 0.5 and 24 h after treatment. At 9 days after treatment, E content showed significant depletion in the innervated gland.The results of this study indicate that melatonin modulates catechol hormone content in avian adrenal medulla, and also regulates glucose homoeostasis (except in the crow). The splanchnic nerve plays a vital role in the synthesis of NE but has no effect on E.

Influence of age on diurnal rhythms of adrenal norepinephrine, epinephrine, and corticosterone levels in soft-shelled turtles (Lissemys punctata punctata)

An investigation was made of what role aging plays on diurnal rhythms of norepinephrine, epinephrine, and corticosterone contents in the adrenal gland of soft-shelled turtles. To resolve this problem, juvenile and adult soft-shelled turtles were sacrificed at four different time intervals (0600, 1200, 1800, and 2400 hr) and adrenal hormonal levels were measured by spectrofluorometer. The findings revealed that peak norepinephrine, epinephrine, and corticosterone values were observed at 2400, 0600, and 2400 hr, respectively, and trough values for all the hormones were found at 1200 hr in both juvenile and adult animals. Thus, diurnal rhythms for all the hormones studied exist in both juvenile and adult animals. It is suggested that aging apparently has no influence on diurnal variations of adrenal hormones in turtles.

Circadian rhythms in serotonin, norepinephrine, and epinephrine contents of the pineal-paraphyseal complex of the soft-shelled turtle (Lissemys punctata punctata)

Diurnal variations in pineal serotonin, norepinephrine, and epinephrine levels were measured at four different time intervals (06:00, 12:00, 18:00, and 24:00 hr) in adult male soft-shelled turtles. The serotonin level increased during day and decreased during night. But the norepinephrine and epinephrine levels showed reverse changes. The findings reveal that there is a distinct circadian rhythm in serotonin, norepinephrine, and epinephrine contents of the pineal-paraphyseal complex in adult male soft-shelled turtles.

Influence of splanchnic nerve on reserpine action in avian adrenal medulla

Reserpine at three doses (0.05, 0.2, and 0.8 mg/100 g body wt) has been injected intraperitoneally to seven unilaterally splanchnic denervated avian species, in order to ascertain the neural regulation of its action in avian adrenal medulla. The adrenomedullary catecholamines (CA) were estimated at 24 hr after reserpine injection. The findings revealed that reserpine at high doses caused 66-92% depletion of total CA from both the innervated and the denervated glands in all the species investigated. The low dose of reserpine in the passerine (common myna and bulbul) birds resulted in 40-84% reduction of both norepinephrine (NE) and epinephrine (E) from the adrenal glands irrespective of its nerve supply. As a contrast, it depleted 60-80% of both NE and E from the innervated glands as compared to 17-43% reduction from the denervated glands in nonpasserine (woodpecker, parakeet, and koel) birds. Interestingly, in other nonpasserine (pigeon and duck) birds, the low dose of reserpine depleted 66-71% of NE from the innervated glands as compared to only 2-13% reduction from the denervated glands. But in these birds, 60-85% depletion of E, however, occurred independent of neural regulation. The findings suggest that at high doses depletion of CA by reserpine is controlled by some nonneurogenic mechanisms. Generally speaking, at a low dose of reserpine, the splanchnic nerve probably modulates depletion of CA from the adrenal medulla of the nonpasserine birds while the same is governed by some nonneurogenic mechanisms in the passerine birds.

Circadian rhythms and influence of light on serotonin, norepinephrine, and epinephrine contents in the pineal-paraphyseal complex of soft-shelled turtles (Lissemys punctata punctata)

The aims of the current investigation were to examine the circadian rhythms in the pineal-paraphyseal amines and indoleamine in juvenile turtles. An attempt was also made to study the influence of photoperiod on pineal activities in adult turtles. Serotonin, norepinephrine, and epinephrine levels were studied at four different time intervals (0600, 1200, 1800, and 2400 hr) of a 24-hr period. Increased serotonin level was observed during day and trough values during night, but the norepinephrine and epinephrine levels showed reverse changes. Continuous light (24L:0D) or long photoperiod (22L:2D) resulted in an elevation of serotonin level and diminution of norepinephrine level, but continuous darkness (0L:24D) or short photoperiod (2L:22D) showed reverse changes. Epinephrine level altered in parallel to that of norepinephrine with long (22L:2D) or short (2L:22D) photoperiod, but remained unaltered with continuous light (24L:0D) or continuous darkness (0L:24D). It is suggested that circadian rhythms exist in pineal-paraphyseal amines and indoleamine in juvenile turtles like that of adult turtles. It is also suggested that light greatly modulates serotonin, norepinephrine, and epinephrine contents in the pineal-paraphyseal complex of the soft-shelled turtle.

Influence of age on adrenomedullary catechol hormones content in twenty‐five avian species

Abstract Catechol hormones (Norepinephrine and Epinephrine) content in the adrenal medulla of 25 species of the newly‐hatched and adult birds were investigated. Norepinephrine (NE) and Epinephrine (E) were found to be the major hormones in the adrenal medulla of the newly‐hatched passerine and non‐passerine birds respectively. E was the preponderant hormone in the adrenal medulla of the adult passerine birds. The adrenal medulla of the adult non‐passerine birds produced either NE as the predominant catechol hormone or NE and E in almost equal proportion as the adrenomedullary hormones.

Effect of ambient temperature on serotonin, norepinephrine, and epinephrine contents in the pineal−paraphyseal complex of the soft-shelled turtle (Lissemys punctata punctata)

The aim of the present investigation was to ascertain the influence of ambient temperature on serotonin, norepinephrine, and epinephrine contents in the pineal-paraphyseal complex of soft-shelled turtles. Turtles were exposed to low (10 degrees) and high (32 degrees) temperatures for 7 days in an incubator with the same photoperiod (12L:12D). Control animals were also kept in the same incubator at 25 degrees for similar duration with the same photoperiod. The findings revealed that ambient temperatures significantly altered serotonin, norepinephrine, and epinephrine content in the pineal-paraphyseal complex of turtles. The results thus indicate that ambient temperature has some influence on pineal serotonin, norepinephrine, and epinephrine contents in soft-shelled turtles.

EFFECT OF STRESS ON SEROTONIN, NOREPINEPHRINE, EPINEPHRINE AND CORTICOSTERONE CONTENTS IN THE SOFT-SHELLED TURTLE

1. Adult soft‐shelled turtles were exposed to hyperosmotic and dehydration stresses.

Effect of insulin on serotonin, 5-hydroxyindole-acetic acid, norepinephrine, epinephrine and corticosterone contents in chick

Pineal serotonin (5-HT), 5-hydroxyindole-acetic acid (5-HIAA), norepinephrine (NE), epinephrine (E) and adrenal corticosterone, NE and E contents were measured spectrofluorometrically 5, 15, 30 and 60 min after insulin treatment to induce hypoglycemic stress. In the pineal gland, hypoglycemic stress caused dramatic decrease of 5-HT, resulted in initial decrease followed by an increase of 5-HIAA and brought about changes of NE and E. Corticosterone content in the adrenal gland increased significantly following treatment with insulin. Adrenal NE and E contents plummetted to control value followed by quick resynthesis. The findings indicate that insulin-induced hypoglycemia greatly modulates the activities of pineal and adrenal glands.

Effect of melatonin on norepinephrine, epinephrine, and corticosterone contents in the adrenal gland of three avian species

SummaryA single melatonin injection was administered intraperitoneally to three avian species in two doses (250 and 500 μg · 100 g body wt−1). Norepinephrine (NE), epinephrine (E), and corticosterone (C) contents of the adrenal gland were measured spectrofluorometrically 0.5, 2, and 24 h after injection. The results showed that melatonin at the lower dose caused a decrease of NE content in bulbul (42%), babbler (52%), and pigeon (39%), while at the higher dose it resulted in a decrease of NE only in bulbul (51%) 0.5 h after treatment. Melatonin at the lower dose also caused a decrease of NE in bulbul (45%) and babbler (53%) 2 and 24 h, respectively, after treatment, while at the higher dose it resulted in an increase of NE in bulbul (82%) and a decrease of NE in babbler (44%) 24 h after injection.Both low and high doses of melatonin resulted in a decrease of E content in bulbul (32–43%), babbler (34–43%), and pigeon (44–56%) 0.5 h after treatment, and a 34–46% decrease of E in bulbul and a 32–33% decrease of E in babbler 2 h after treatment. A 57% decrease of E was evident in pigeon with the lower dose of melatonin 2 h after injection. Melatonin at the higher dose caused a 67% increase of E in babbler and a 41% decrease of E in pigeon 24 h after administration. Melatonin at the lower dose resulted in an increase of C content in bulbul (70%), babbler (132%), and pigeon (69%) 0.5 h after treatment. A 60% increase of C was evident in pigeon following the lower dose of melatonin 24 h after injection. Melatonin at the higher dose resulted in an increase of C in the bulbul of 72% and 86% at 0.5 and 24 h, respectively, after treatment. The results indicate that melatonin produces significant changes of NE, E, and C contents in three avian species. The lower dose appears to be more effective in changing NE and C content.