Intracerebroventricular administration of growth hormone induces morphological changes in pyramidal neurons of the hippocampus and prefrontal cortex in adult rats

• Published in: Synapse (New York, N.Y.) N.Y.), 2018-07, Vol.72 (7), p.e22030-n/a
• Main Authors: Olivares‐Hernández, Juan David, García‐García, Fabio, Camacho‐Abrego, Israel, Flores, Gonzalo, Juárez‐Aguilar, Enrique
• Format: Article
• Language: English
• Subjects: Animals; Brain; CA1 Region, Hippocampal - cytology; Dendrites - drug effects; Dendritic branching; dendritic morphology; Dendritic plasticity; Dendritic spines; Golgi‐Cox staining; Growth Hormone - administration & dosage; Growth Hormone - pharmacology; Growth hormones; Hippocampus; Humans; Injections, Intraventricular; Intracerebroventricular administration; Male; Morphology; Neurons; Prefrontal cortex; Prefrontal Cortex - cytology; Pyramidal cells; Pyramidal Cells - cytology; Pyramidal Cells - drug effects; Rats; Rats, Wistar; Rodents; somatotropin; structural plasticity; Synaptic plasticity
• ISSN: 0887-4476; 1098-2396
• DOI: 10.1002/syn.22030

A growing body of evidence suggests that growth hormone (GH) affects synaptic plasticity at both the molecular and electrophysiological levels. However, unclear is whether plasticity that is stimulated by GH is associated with changes in neuron structure. This study investigated the effect of intracerebroventricular (ICV) administration of GH on the morphology of pyramidal neurons of the CA1 region of the dorsal hippocampus and layer III of the prefrontal cortex. Male Wistar rats received daily ICV injections of GH (120 ng) for 7 days, and they were euthanized 21 days later. Changes in neuronal morphology were evaluated using Golgi‐Cox staining and subsequent Sholl analysis. GH administration increased total dendritic length in the CA1 region of the dorsal hippocampus and prefrontal cortex. The Sholl analysis revealed an increase in dendritic length of the third to eighth branch orders in the hippocampus and from the third to sixth branch orders in the prefrontal cortex. Interestingly, GH treatment increased the density of dendritic spines in both brain regions, favoring the presence of mushroom‐like spines only in the CA1 hippocampal region. Our results indicated that GH induces changes in the length of dendritic trees and the density of dendritic spines in two high‐plasticity brain regions, suggesting that GH‐induced synaptic plasticity at the molecular and electrophysiological levels may be associated with these structural changes in neurons. The intracerebroventricular administration of growth hormone (GH) increases the total dendritic length of pyramidal neurons in the prefrontal cortex and in the CA1 region of hippocampus. The effect of this hormone on structural plasticity could explain the mnemonic and restorative effects related with GH in rodents and humans.