Norepinephrine does not alter NPY and POMC mRNA expression in neonatal chicks
Sachiko Katayama1, Shozo Tomonaga, Momoka Sato
1Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan.
Summary
Norepinephrine (NE) injection reduced food intake in chicks but did not alter Neuropeptide Y (NPY) or Proopiomelanocortin (POMC) gene expression in the brain. This suggests NE
Area of Science:
- Neuroscience
- Animal Science
- Endocrinology
Background:
- Norepinephrine (NE) regulates food intake in mammals and chickens.
- Neuropeptide Y (NPY) and Proopiomelanocortin (POMC) are key appetite mediators.
- NE and NPY interact in the central and peripheral nervous systems.
Purpose of the Study:
- To investigate the effect of intracerebroventricular (ICV) NE on food intake and appetite mediators in neonatal chicks.
- To examine changes in NPY and POMC mRNA expression following NE administration.
Main Methods:
- Two experiments were conducted on neonatal chicks (Gallus gallus).
- Experiment 1: ICV injection of varying NE doses (0-100 microg) after fasting, measuring food intake and CNS NPY mRNA.
- Experiment 2: ICV injection of NE (50 microg) in fed chicks, measuring brain NPY and POMC mRNA levels.
Main Results:
- ICV NE dose-dependently reduced food intake in fasted chicks.
- No significant changes in NPY mRNA were observed in the CNS in Experiment 1.
- No significant changes in brain NPY or POMC mRNA levels were found in Experiment 2.
Conclusions:
- Central NE administration effectively reduces food intake in neonatal chicks.
- ICV NE injection does not appear to alter NPY or POMC gene expression in the chick brain.
- The anorectic effect of NE may not be mediated through direct changes in NPY or POMC mRNA levels.
Related Concept Videos
01:27Adrenergic Neurons: Neurotransmission
Postganglionic sympathetic fibers (except those supplying the sweat glands) releasing noradrenaline or norepinephrine are called noradrenergic or adrenergic neurons. Noradrenaline, dopamine, adrenaline, or epinephrine are collectively called "catecholamines" as they contain a catechol moiety and an amine side chain. The five stages of neurotransmitter release involve their synthesis, storage, release, reuptake and metabolism.
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
01:26Adrenergic Receptors: β Subtype
β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
01:29Drugs Affecting Neurotransmitter Synthesis
Drugs affecting neurotransmitter synthesis can impact the adrenergic neuron and the synthesis of neurotransmitters. For example, α-methyltyrosine and carbidopa target specific enzymes involved in catecholamine synthesis. α-methyltyrosine inhibits the enzyme tyrosine hydroxylase, which converts tyrosine into dopamine. By blocking this enzyme, α-methyltyrosine reduces dopamine production and other catecholamines. Carbidopa, on the other hand, inhibits the enzyme dopa decarboxylase, which converts...
01:31Sympathetic Signaling
Sympathetic signaling, a vital part of the autonomic nervous system, plays a crucial role in mobilizing the body's resources in response to stress or emergencies. It involves the transmission of nerve impulses from sympathetic preganglionic fibers to postganglionic fibers. This results in the release of specific neurotransmitters and activation of adrenergic receptors.
Sympathetic preganglionic fibers release the neurotransmitter acetylcholine (ACh) onto the ganglionic neurons in the...
Sympathetic preganglionic fibers release the neurotransmitter acetylcholine (ACh) onto the ganglionic neurons in the...
01:30Regulation of Food Intake
Short-term regulation of food intake primarily involves neural signals from the gastrointestinal (GI) tract, blood nutrient levels, and GI tract hormones. Communication between the gut and brain via vagal nerve fibers plays a significant role in evaluating the contents of the gut. Clinical studies have shown that protein ingestion produces a more prolonged response in these nerve fibers compared to an equivalent amount of glucose. Additionally, the activation of stretch receptors caused by GI...
01:16Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Adrenergic agonists' structure-activity relationship (SAR) determines their selectivity and efficacy. These agonists comprise a phenylethylamine moiety with an aromatic ring and an ethylamine side chain.
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...