Induction of Unseasonable Hibernation and Involvement of Serotonin in Entrance into and Maintenance of Its Hibernation of Chipmunks T. asiaticus.

Abstract

ABSTRACT. Chipmunks that had been housed at 22°C under a light-dark cycle of 14L:10D for at least one year were exposed to a short photoperiod (10L:14D) and low temperature to induce unseasonable hibernation. We were able to induce hibernation at any time of year and there was no significant difference in the duration of the hibernation bout, the duration of interbout euthermia and duration of bouts of torpor throughout the year; however entrance into hibernation took about 60 days in summer but only about 30 days in any other seasons. In addition, interbout euthermia predominantly occurred during the light phase in winter, whereas in spring interbout euthermia occurred equally in the light and dark phases. These results suggest that both the circadian and circannual systems are linked to hibernation in chipmunks. Subcutaneous infusion of a serotonin antagonist, para-chlorophenylalanine (PCPA), facilitated entrance into and interrupted hibernation in aroused and hibernating chipmunks in summer, respectively. On the other hand, opioid antagonist, naloxone, did not affect hibernation, but extended the period of interbout euthermia. These results suggest that the role of serotonin in entrance into and maintenance of hibernation in chipmunks is independent of the circannual system, and that opioid system may not be involved in hibernation in chipmunks.KEY WORDS: circadian rhythm, circannual rhythm, hibernation.

Hibernation induces pentobarbital insensitivity in medulla but not cortex

“…Liganddriven mechanisms controlling hibernation have been investigated for more than 30 years (22,38,48). Some of the proposed molecules include circulating hormones such as vasopressin (21), and neurotransmitters, such as serotonin (45), histamine (61), and GABA (49). The GABAergic system is a logical candidate for the induction and maintenance of systemwide CNS inhibition during torpor.…”

Hibernation induces pentobarbital insensitivity in medulla but not cortex

“…Liganddriven mechanisms controlling hibernation have been investigated for more than 30 years (22,38,48). Some of the proposed molecules include circulating hormones such as vasopressin (21), and neurotransmitters, such as serotonin (45), histamine (61), and GABA (49). The GABAergic system is a logical candidate for the induction and maintenance of systemwide CNS inhibition during torpor.…”

Season of Sampling and Season of Birth Influence Serotonin Metabolite Levels in Human Cerebrospinal Fluid

“…hibernation) on the one hand and serotonin (5-hydroxytryptamine, 5-HT) metabolism on the other [16], [17], [18], [19]. For example, in rhesus macaques, the main metabolite of 5-HT (5-hydroxyindoleacetic acid, 5-HIAA) in cerebrospinal fluid (CSF) is highest during the mating season and correlates positively with several measures of successful mating [17], [19].…”

Metabolic depression in Cyclorana alboguttata and the potential role of the endogenous opioid system and thyroid axis as regulators of aestivation

“…Canguilhem et al (1986) found brain serotonin levels to both increase and decrease during entrance into torpor during hibernation, depending on the part of the brain examined, and Naumenko et al (2008) found the density of serotonergic receptors increased or decreased in different regions of the brain during torpor in the ground squirrel Spermophilus undulatus, but Hernadi et al (2008) found firing of the serotonergic neurons decreased during aestivation in H. pomatia. Murakami et al (2000) found the serotonin antagonist, PCPA, facilitated entrance into torpor in active animals, but also arousal from metabolic depression in hibernating animals. Melatonin, which is important in the regulation of circadian rhythms and is synthesised from serotonin, has also been implicated in the initiation of hibernation.…”

“…In addition, despite advances in scientific methodologies and technology, the chemical and genetic identity of HIT remains unsolved. Canguilhem et al, 1986;Hernadi et al, 2008;Michaelidis et al, 2002;Murakami et al, 2000;Popova and Voitenko, 1981;Tsiouris, 2005) Melatonin I ↓ (Palmer and Riedesel, 1976;Revel et al, 2007) Dopamine ↔ ↓ ↑ (Hernadi et al, 2008;Michaelidis et al, 2002;Milton and Lutz, 1998;Wang et al, 2008) GABA ↑ ↔ (Al-Badry and Taha, 1982;Michaelidis et al, 2002;Mihailović et al, 1965;Nilsson et al, 1991;Osborne and Hashimoto, 2008;Raheem and El Mosallamy, 1979) Adenosine ↓ ↑ (Michaelidis et al, 2002;Nilsson and Lutz, 1992) TRH ↓ ↑ ↓ RB I (Ignatiev et al, 1995;Kreider et al, 1990;Stanton et al, 1992;Stanton et al, 1980;Stanton et al, 1982;Young et al, 1979b) AVP ↓ B ↔ RE ↑ RE ↓ M I (Hermes et al, 1989;Hermes et al, 1993;Revel et al, 2007) Urea I ↑ ↔ F L (Hiong et al, 2005;Loong et al, 2008;Muir et al, 2007;Muir et al, 2008;Rees and Hand, 1993) HIT* I (Dawe and Spurrier, 1969;Oeltgen et al, 1978;Oeltgen et al, 1985;Oeltgen and Spurrier, 1983;…”

Hibernation induces pentobarbital insensitivity in medulla but not cortex

“…Liganddriven mechanisms controlling hibernation have been investigated for more than 30 years (22,38,48). Some of the proposed molecules include circulating hormones such as vasopressin (21), and neurotransmitters, such as serotonin (45), histamine (61), and GABA (49). The GABAergic system is a logical candidate for the induction and maintenance of systemwide CNS inhibition during torpor.…”

Season of Sampling and Season of Birth Influence Serotonin Metabolite Levels in Human Cerebrospinal Fluid

“…hibernation) on the one hand and serotonin (5-hydroxytryptamine, 5-HT) metabolism on the other [16], [17], [18], [19]. For example, in rhesus macaques, the main metabolite of 5-HT (5-hydroxyindoleacetic acid, 5-HIAA) in cerebrospinal fluid (CSF) is highest during the mating season and correlates positively with several measures of successful mating [17], [19].…”

Metabolic depression in Cyclorana alboguttata and the potential role of the endogenous opioid system and thyroid axis as regulators of aestivation

“…Canguilhem et al (1986) found brain serotonin levels to both increase and decrease during entrance into torpor during hibernation, depending on the part of the brain examined, and Naumenko et al (2008) found the density of serotonergic receptors increased or decreased in different regions of the brain during torpor in the ground squirrel Spermophilus undulatus, but Hernadi et al (2008) found firing of the serotonergic neurons decreased during aestivation in H. pomatia. Murakami et al (2000) found the serotonin antagonist, PCPA, facilitated entrance into torpor in active animals, but also arousal from metabolic depression in hibernating animals. Melatonin, which is important in the regulation of circadian rhythms and is synthesised from serotonin, has also been implicated in the initiation of hibernation.…”

“…In addition, despite advances in scientific methodologies and technology, the chemical and genetic identity of HIT remains unsolved. Canguilhem et al, 1986;Hernadi et al, 2008;Michaelidis et al, 2002;Murakami et al, 2000;Popova and Voitenko, 1981;Tsiouris, 2005) Melatonin I ↓ (Palmer and Riedesel, 1976;Revel et al, 2007) Dopamine ↔ ↓ ↑ (Hernadi et al, 2008;Michaelidis et al, 2002;Milton and Lutz, 1998;Wang et al, 2008) GABA ↑ ↔ (Al-Badry and Taha, 1982;Michaelidis et al, 2002;Mihailović et al, 1965;Nilsson et al, 1991;Osborne and Hashimoto, 2008;Raheem and El Mosallamy, 1979) Adenosine ↓ ↑ (Michaelidis et al, 2002;Nilsson and Lutz, 1992) TRH ↓ ↑ ↓ RB I (Ignatiev et al, 1995;Kreider et al, 1990;Stanton et al, 1992;Stanton et al, 1980;Stanton et al, 1982;Young et al, 1979b) AVP ↓ B ↔ RE ↑ RE ↓ M I (Hermes et al, 1989;Hermes et al, 1993;Revel et al, 2007) Urea I ↑ ↔ F L (Hiong et al, 2005;Loong et al, 2008;Muir et al, 2007;Muir et al, 2008;Rees and Hand, 1993) HIT* I (Dawe and Spurrier, 1969;Oeltgen et al, 1978;Oeltgen et al, 1985;Oeltgen and Spurrier, 1983;…”

Hibernation induces pentobarbital insensitivity in medulla but not cortex

“…Liganddriven mechanisms controlling hibernation have been investigated for more than 30 years (22,38,48). Some of the proposed molecules include circulating hormones such as vasopressin (21), and neurotransmitters, such as serotonin (45), histamine (61), and GABA (49). The GABAergic system is a logical candidate for the induction and maintenance of systemwide CNS inhibition during torpor.…”

Season of Sampling and Season of Birth Influence Serotonin Metabolite Levels in Human Cerebrospinal Fluid

“…hibernation) on the one hand and serotonin (5-hydroxytryptamine, 5-HT) metabolism on the other [16], [17], [18], [19]. For example, in rhesus macaques, the main metabolite of 5-HT (5-hydroxyindoleacetic acid, 5-HIAA) in cerebrospinal fluid (CSF) is highest during the mating season and correlates positively with several measures of successful mating [17], [19].…”

Metabolic depression in Cyclorana alboguttata and the potential role of the endogenous opioid system and thyroid axis as regulators of aestivation

“…Canguilhem et al (1986) found brain serotonin levels to both increase and decrease during entrance into torpor during hibernation, depending on the part of the brain examined, and Naumenko et al (2008) found the density of serotonergic receptors increased or decreased in different regions of the brain during torpor in the ground squirrel Spermophilus undulatus, but Hernadi et al (2008) found firing of the serotonergic neurons decreased during aestivation in H. pomatia. Murakami et al (2000) found the serotonin antagonist, PCPA, facilitated entrance into torpor in active animals, but also arousal from metabolic depression in hibernating animals. Melatonin, which is important in the regulation of circadian rhythms and is synthesised from serotonin, has also been implicated in the initiation of hibernation.…”

“…In addition, despite advances in scientific methodologies and technology, the chemical and genetic identity of HIT remains unsolved. Canguilhem et al, 1986;Hernadi et al, 2008;Michaelidis et al, 2002;Murakami et al, 2000;Popova and Voitenko, 1981;Tsiouris, 2005) Melatonin I ↓ (Palmer and Riedesel, 1976;Revel et al, 2007) Dopamine ↔ ↓ ↑ (Hernadi et al, 2008;Michaelidis et al, 2002;Milton and Lutz, 1998;Wang et al, 2008) GABA ↑ ↔ (Al-Badry and Taha, 1982;Michaelidis et al, 2002;Mihailović et al, 1965;Nilsson et al, 1991;Osborne and Hashimoto, 2008;Raheem and El Mosallamy, 1979) Adenosine ↓ ↑ (Michaelidis et al, 2002;Nilsson and Lutz, 1992) TRH ↓ ↑ ↓ RB I (Ignatiev et al, 1995;Kreider et al, 1990;Stanton et al, 1992;Stanton et al, 1980;Stanton et al, 1982;Young et al, 1979b) AVP ↓ B ↔ RE ↑ RE ↓ M I (Hermes et al, 1989;Hermes et al, 1993;Revel et al, 2007) Urea I ↑ ↔ F L (Hiong et al, 2005;Loong et al, 2008;Muir et al, 2007;Muir et al, 2008;Rees and Hand, 1993) HIT* I (Dawe and Spurrier, 1969;Oeltgen et al, 1978;Oeltgen et al, 1985;Oeltgen and Spurrier, 1983;…”