Concurrent modulation of extracellular levels of noradrenaline and cAMP during stress and by anxiogenic- or anxiolytic-like neuropeptides in the prefrontal cortex of awake rats
Graphical abstract
Highlights
► Novel HPLC fluorescence derivatization method for determination of cAMP. ► Microdialysis monitoring of stress-induced release of noradrenaline and cAMP in rat mPFC. ► Anxiogenic and anxiolytic peptides differentially modulate noradrenaline and cAMP.
Introduction
Microdialysis is a well-established in vivo sampling technique for monitoring presynaptic events including neurotransmitter release, reuptake and metabolism (for review, see Kehr and Yoshitake, 2006). In addition, a number of reports have described a feasibility of using microdialysis also for monitoring the postsynaptic actions including sampling the molecules involved in intracellular signalling cascades and being able to traverse, at least partly, into the extracellular fluid (Egawa et al., 1988, Vallebuona and Raiteri, 1993). There is evidence from both in vitro and in vivo studies that intracellular cyclic AMP (cAMP) is able to leak, egress into the extracellular space and most importantly, that there is a linear relationship between the intracellular cAMP concentrations and the efflux rate of cAMP into the extracellular compartment. Thus, the egress of cAMP in cultured cell lines was shown to account for about 15–18% of the total turnover of cAMP and it was concluded that the efflux process was most likely driven by active, energy-dependent mechanisms rather than just passive diffusion (Barber and Butcher, 1980). Similar findings were reported for tissue slices (Lazareno et al., 1985, Stoof and Kebabian, 1981) and for in vivo experiments carried out first, by use of the push–pull cannula (Korf et al., 1976, Schoener et al., 1979) and then by microdialysis (the year would indicate that it’s not “lately”, I’d use “then” instead) (Egawa et al., 1988). The subsequent microdialysis studies have demonstrated that the increased production of extracellular cAMP in cortical and hippocampal areas was strongly correlated to increased noradrenergic stimulation. Thus, both noradrenaline (NA) and cAMP levels increased in response to stress caused by immobilization or by intraperitoneal injection of saline (Stone and John, 1992) or by pharmacological means (Egawa et al., 1988, Montezinho et al., 2006, Montezinho et al., 2007, Mork, 1993, Mork and Geisler, 1995, Stone and John, 1991). Infusion of NA via the probe implanted in the rat frontal cortex caused a dose-dependent increase in cAMP efflux and this effect was blocked by infusion of the β-adrenoceptor antagonist, timolol, indicating that the NA-induced cAMP efflux is mediated primarily by activation of β-receptors (Egawa et al., 1988). This conclusion was confirmed by the following microdialysis studies showing that stimulation of β-adrenoceptors with isoproterenol or forskolin increased the extracellular cAMP levels in the rat medial prefrontal cortex (mPFC) and these effects were significantly inhibited by mood stabilizers such as/including lithium, carbamazepine, or valproate (Montezinho et al., 2006, Montezinho et al., 2007). These microdialysis data together with a large number of behavioural and pharmacological studies (for review, see Morilak et al., 2005) suggest a role of NA and cAMP in mediating stress and anxiety responses.
Several neuropeptides and their respective receptors are expressed in the central nervous system, including the prefrontal cortex, hippocampus and amygdala, the major anatomical structures implemented in modulation of cognitive functions, as well as affective behaviours (for review, see Ebner et al., 2009, Hökfelt et al., 2000, McGonigle, 2012, Ögren et al., 2010). Thus, neuropeptides including galanin, NPY, nociceptin/orphanin FQ, somatostatin and their receptors are predominantly inhibitory being coupled to Gi/o protein-coupled receptors (GPCRs), whereas cholecystokinin octapeptide (CCK-8) and vasopressin receptors are stimulatory Gs or Gq/11 GPCRs and neurotensin, substance P and neurokinin A receptors are Gq/11 GPCRs (Alexander et al., 2011). A body of evidence exists for the role of these peptides in regulation of stress responses, which in turn are strongly linked to the aetiology of affective disorders including depression, anxiety, panic attack, posttraumatic stress disorder, anorexia or fibromyalgia (Ebner et al., 2009, Engin et al., 2008, Feifel et al., 1999, Fernandez et al., 2004, Goeldner et al., 2012, Heilig et al., 1989, McGonigle, 2012, Ögren et al., 2010). However, how the neuropeptides may modulate NA release and correspondingly, the extracellular cAMP levels in vivo in relevant neuroanatomical structures is yet not fully elucidated. The purpose of the present study was to investigate, by use of microdialysis, whether local infusions of nine representative neuropeptides with proposed anxiogenic or anxiolytic properties to separate groups of rats could affect the extracellular levels of NA and cAMP and how these potential effects could correlate to the stress-induced responses in NA and cAMP efflux in mPFC of awake rats. The extracellular levels of cAMP in the microdialysis samples were determined by a newly developed high-sensitive and selective liquid chromatographic method based of precolumn derivatization with 2-chloroacetaldehyde and fluorescence detection.
Section snippets
Chemicals and solutions
Noradrenaline hydrochloride (NA), adenosine 3′,5′-cyclic monophosphate sodium salt (cAMP), sodium potassium chloride, phosphate monobasic monohydrate, sodium phosphate dibasic were obtained from Sigma (St. Louis, MO, USA). Methanol was purchased from Merck (Darmstadt, Germany), EDTA-2Na was obtained from Dojindo (Kumamoto, Japan). Forskolin was obtained from Wako Pure Chemicals (Osaka, Japan). Galanin (porcine) and nociceptin/orphanin FQ were purchased from Bachem (Bubendorf, Switzerland).
Basal and stimulated levels of cAMP and NA
The initial part of the study was focused on validation of the HPLC method developed for determination of cAMP in the microdialysis samples from the rat mPFC at basal conditions and following local stimulation with forskolin, and NA. Fig. 1A shows typical chromatograms of (a) aCSF blank solution and (b, c) standard solutions containing cAMP at concentrations of 6 fmol (b) and 60 fmol (c) in 10 μl samples derivatized with 10 μl of the 2-chloroacetaldehyde reagent. Other adenine compounds ATP, ADP,
Discussion
The purpose of this study was to examine effects of stress and the role of exogenously infused neuropeptides, galanin, CCK-8, vasopressin, nociceptin/orphanin FQ, somatostatin, neurotensin, NPY, substance P and neurokinin A, on modulation of NA release and cAMP efflux monitored by microdialysis in the mPFC of awake rats. Concentrations of cAMP in the microdialysates were determined by a newly developed sensitive chromatographic method based on derivatization of cAMP with 2-chloroacetaldehyde
Conclusions
In the present study, microdialysis samples were collected from the mPFC of awake rats and the extracellular cAMP and NA levels were determined simultaneously by two separate HPLC systems with fluorescence detection (cAMP) and electrochemical detection (NA). The results confirmed that there is a close correlation between the stress-induced increases in prefrontal cortical NA and cAMP levels. However, monitoring the NA and cAMP levels, following local infusions of some selected neuropeptides
Acknowledgements
The authors have no conflict of interest to declare.
References (84)
- et al.
The distribution of cholecystokinin immunoreactivity in the central nervous system of the rat as determined by radioimmunoassay
Brain Res.
(1981) Vasopressin receptors
Trends Endocrinol. Metab.
(2000)- et al.
Galanin receptor subtypes
Trends Pharmacol. Sci.
(2000) - et al.
Prenatal restraint stress: an in vivo microdialysis study on catecholamine release in the rat prefrontal cortex
Neuroscience
(2010) - et al.
Anxiolytic-like effect of central administration of NOP receptor antagonist UFP-101 in rats submitted to the elevated T-maze
Behav. Brain Res.
(2011) - et al.
Use of microdialysis to measure brain noradrenergic receptor function in vivo
Brain Res.
(1988) - et al.
Anxiolytic and antidepressant effects of intracerebroventricularly administered somatostatin: behavioral and neurophysiological evidence
Neuroscience
(2008) - et al.
Increased dopamine and norepinephrine release in medial prefrontal cortex induced by acute and chronic stress: effects of diazepam
Neuroscience
(1995) - et al.
Autoradiographic localization of [3H]nociceptin binding sites in the rat brain
Brain Res.
(2000) - et al.
Preferential blockade of cholecystokinin-8S-induced increases in aspartate and glutamate levels by the CCK(B) receptor antagonist, L-365,260, in rat brain
Eur. J. Pharmacol.
(1998)
Effect of local cholecystokinin-8 administration on extracellular levels of amino acids and glycolytic products monitored by in vivo microdialysis in the fronto-parietal cortex of the rat
Neurosci. Lett.
Neuropeptide Y modulates the antidepressant activity of imipramine in olfactory bulbectomized rats: involvement of NPY Y1 receptors
Brain Res.
In vivo cyclic AMP responses in rat brain are not modified by chronic electroconvulsive shock
Eur. Neuropsychopharmacol.
Rats with anxious or non-anxious type of exploratory behaviour differ in their brain CCK-8 and benzodiazepine receptor characteristics
Behav. Brain. Res.
Neuropeptides – an overview
Neuropharmacology
Expression of cholecystokinin and enkephalin mRNA in discrete brain regions
Peptides
Simultaneous determination of six adenyl purines in human plasma by high-performance liquid chromatography with fluorescence derivatization
J. Chromatogr. B Biomed. Sci. Appl.
The role of afferents to the locus coeruleus in the handling stress-induced increase in the release of noradrenaline in the medial prefrontal cortex: a dual-probe microdialysis study in the rat brain
Eur. J. Pharmacol.
CYCLIC AMP/∗SECRETl cyclic AMP into push-pull perfusates in freely moving rats
Brain Res.
Differential effects of selective and non-selective neuroleptics on intracellular and extracellular cyclic AMP accumulation in rat striatal slices
Brain Res.
The novel neurotensin analog NT69L blocks phencyclidine (PCP)-induced increases in locomotor activity and PCP-induced increases in monoamine and amino acids levels in the medial prefrontal cortex
Brain Res.
Afferent projections to the rat locus coeruleus demonstrated by retrograde and anterograde tracing with cholera-toxin B subunit and Phaseolus vulgaris leucoagglutinin
Neuroscience
Distribution of the substance P receptor (NK-1 receptor) in the central nervous system
Brain Res. Mol. Brain Res.
Peptide therapeutics for CNS indications
Biochem. Pharmacol.
Role of brain norepinephrine in the behavioral response to stress
Prog. Neuropsychopharmacol. Biol. Psychiatry
Interactions of norepinephrine and galanin in the central amygdala and lateral bed nucleus of the stria terminalis modulate the behavioral response to acute stress
Life Sci.
Neuropeptides in learning and memory processes with focus on galanin
Eur. J. Pharmacol.
The neuropeptide galanin as an in vivo modulator of brain 5-HT1A receptors: possible relevance for affective disorders
Physiol. Behav.
Effects of nociceptinNH2 and [Nphe1]nociceptin(1 ± 13)NH2 on rat brain noradrenaline release in vivo and in vitro
Neuroscience Lett.
Saredutant, an NK2 receptor antagonist, has both antidepressant-like effects and synergizes with desipramine in an animal model of depression
Pharmacol. Biochem. Behav.
Central administration of NPY or an NPY-Y5 selective agonist increase in vivo extracellular monoamine levels in mesocorticolimbic projecting areas
Neuropharmacology
Fluorometric determination of adenine nucleotides and adenosine by ion-paired, reverse-phase, high-performance liquid chromatography
Anal. Biochem.
The neuropeptide Y (NPY) Y1 receptor subtype mediates NPY-induced antidepressant-like activity in the mouse forced swimming test
Neuropsychopharmacology
Autoradiographic distribution of tachykinin NK2 binding sites in the rat brain: comparison with NK1 and NK3 binding sites
Neuroscience
Cyclic nucleotides in the rat neostriatum: push-pull perfusion studies
Brain Res.
G protein-coupled-receptor cross-talk: the fine-tuning of multiple receptor-signalling pathways
Trends Pharmacol. Sci.
The neurotensin-1 receptor agonist PD149163 blocks fear-potentiated startle
Pharmacol. Biochem. Behav.
Responsiveness of mesolimbic, mesocortical, septal and hippocampal cholecystokinin and substance-P neuronal systems to stress, in the male rat
Neurochem. Int.
Further evidence for a glial localization of rat cortical beta-adrenoceptors: studies of in vivo cyclic AMP responses to catecholamines
Brain Res.
Stress-induced increase of extracellular levels of cyclic AMP in rat cortex
Brain Res.
Monitoring of cyclic GMP during cerebellar microdialysis in freely-moving rats as an index of nitric oxide synthase activity
Neuroscience
Guide to Receptors and Channels (GRAC), 5th edition
Br. J. Pharmacol.
Cited by (12)
Dorsal hippocampal galanin modulates anxiety-like behaviours in rats
2018, Brain ResearchCitation Excerpt :For example, galanin decreased glutamate release in the arcuate nucleus of the hypothalamus (Kinney et al., 1998) and in ventral hippocampal slices (Zini et al., 1993). Additionally, galanin raised extracellular levels of noradrenaline in the medial prefrontal cortex (Yoshitake et al., 2013). The effects of galanin on anxiety may depend on the site of drug administration, on the galanin receptor subtypes activated and on the animal models of anxiety employed (Barrera et al., 2005; Holmes and Picciotto, 2006; Soares et al., 2016).
RNA aptamer based electrochemical biosensor for sensitive and selective detection of cAMP
2015, Biosensors and BioelectronicsCitation Excerpt :Therefore, establishing a simple, rapid, accurate and sensitive method to trace the cAMP concentration is essential for disease diagnosis and prevention, as well as new drug design, etc. Traditional biochemical approaches, such as radioimmunoassay (RIA) (Wang et al., 2012), high performance liquid chromatography (HPLC) (Yoshitake et al., 2013; Ichiki et al., 1992), and enzyme linked immune sorbent assays (ELISA) (Williams, 2004) have been used for decades to measure cAMP concentrations in cells and tissues. However, these methods require complicated sample preparations, expensive equipments and reagents, moreover, they are not able to realize rapid and sensitive cAMP detections.
Nociceptin/Orphanin-FQ Modulation of Learning and Memory
2015, Vitamins and HormonesCitation Excerpt :Such anatomical expression suggests that major cortical and limbic structures may be sensitive to the action of N/OFQ. Indeed, electrophysiological and neurochemical studies have shown that N/OFQ and NOP receptor exert a potent inhibitory actions on neuronal excitability and neurotransmitter release in the neocortex, the septum, the hippocampus, and the amygdala (Meis, 2003; Roberto & Siggins, 2006; Schlicker & Morari, 2000; Uezu et al., 2005; Wang et al., 2010; Yoshitake, Ijiri, Kehr, & Yoshitake, 2013). N/OFQ was also reported to inhibit various forms of synaptic plasticity, such as long-term potentiation (LTP) and long-term depression, which are considered as key cellular mechanisms underlying information storage and memory (Bongsebandhu-phubhakdi & Manabe, 2007; Manabe et al., 1998; Wei & Xie, 1999; Yu & Xie, 1998).
Endogenous opiates and behavior: 2013
2014, PeptidesCitation Excerpt :Amygdala infusions of the ORL-1 agonist, SR-8993 impaired fear memory consolidation in mice and an ORL-1 SNP was associated with human PTSD [63]. Anxiolytic-like neuropeptide infusion in the prefrontal cortex of awake rats decreased OFQ/N [1730]. Naloxone and both DA D1 and D2 receptor antagonists administered into the CA3 ventral hippocampus (CA3) reversed anxiolytic-like behaviors induced by cholestasis in mice [1168].
Nociceptin/orphanin FQ receptor antagonists as innovative antidepressant drugs
2013, Pharmacology and TherapeuticsCitation Excerpt :Additionally, in freely moving rats an in vivo microdialysis study revealed that the activation of NOP receptors in the locus ceruleus reduces noradrenaline efflux in the prefrontal cortex (Okawa et al., 2001). Similarly, a recent study showed that locally infused N/OFQ reduced noradrenaline and cAMP levels in the medial prefronatal cortex of awake rats (Yoshitake et al., 2013). Behavioral findings support an involvement of noradrenergic neurotransmission in the basolateral complex of the amygdala in mediating the amnesic effects of N/OFQ (Roozendaal et al., 2007).