Effects of chronic caffeine exposure during adolescence and subsequent acute caffeine challenge during adulthood on rat brain serotonergic systems

Abstract

Caffeine is the most commonly used drug in the world. However, animal studies suggest that chronic consumption of caffeine during adolescence can result in enhanced anxiety-like behavioral responses during adulthood. One mechanism through which chronic caffeine administration may influence subsequent anxietylike responses is through actions on brainstem serotonergic systems. In order to explore potential effects of chronic caffeine consumption on brainstem serotonergic systems, we evaluated the effects of a 28-day exposure to chronic caffeine (0.3 g/L; postnatal day 28-56) or vehicle administration in the drinking water, followed by 24 h caffeine withdrawal, and subsequent challenge with caffeine (30 mg/kg; s.c.) or vehicle in adolescent male rats. In Experiment 1, acute caffeine challenge induced a widespread activation of serotonergic neurons throughout the dorsal raphe nucleus (DR); this effect was attenuated in rats that had been exposed to chronic caffeine consumption. In Experiment 2, acute caffeine administration profoundly *

Lifetime caffeine and adolescent nicotine exposure in mice: effects on anxiety-like behavior and reward

“…Besides, most studies in animal models focus on a particular period of caffeine exposure (e.g. adolescence 13,[69][70][71][72] or prenatal life 73,74 ), which is usually not paralleled by the pattern of exposure that occurs in humans. Here, we tested the hypothesis that lifetime caffeine exposure alters nicotine effects and increases its reward properties during adolescence.…”

“…14,80 Here, we failed to identify alterations in the expression of hippocampal 5-HT 1A , which suggests that this receptor, in the hippocampus, does not play a critical role in the anxiety-like behavior evoked by lifetime caffeine. Arnold and colleagues 71 showed that caffeine exposure during adolescence does not affect mRNA expression of htr1a, the serotonin 1a receptor gene, however, it downregulates mRNA expression of other proteins involved in serotonergic transmission in the dorsal raphe nucleus of rats. These results suggest that other receptors and brain regions relevant to serotonergic-mediated modulation of anxiety should be investigated.…”

High-fat diet, microbiome-gut-brain axis signaling, and anxiety-like behavior in male rats

“…Previously published methods were used for in situ hybridization histochemistry using oligonucleotide probes [ 37 , 13 . To detect htr1a mRNA, two synthetic anti-sense oligonucleotides, one 49-base oligonucleotide (5′-ACG AAG TTC CTA AGC TGG TGC CTG CTC CCT TCT TTT CCA CCT TCC TGA C-3′, Integrated DNA Technologies, Coralville, IA, USA) complementary to bases 810–858 of rat htr1a mRNA and one 47-base oligonucleotide (5′-GCC TCA CTG CCC CAT TAG TGC ACG GAG TCC CCA CCG CCC TGT TCT CA-3′, Integrated DNA Technologies) complementary to bases 923–969 of rat htr1a mRNA, were used [ 37 .…”

“…No. 28,304, Qiagen, Valencia, CA, USA), and used in an in situ hybridization histochemistry assay as described previously [ 15 , 37 ].…”

The Good, the Bad, and the Deadly: Adenosinergic Mechanisms Underlying Sudden Unexpected Death in Epilepsy

“…Serotonergic neurons in the raphe nuclei are chemosensitive and contribute to the hypercapnic ventilatory response ( Hodges et al, 2008 ; Teran et al, 2014 ). Serotonin release is inhibited by adenosine agonists and enhanced by adenosine antagonists ( Feuerstein et al, 1988 ; Okada et al, 2001 ; Arnold et al, 2019 ). Similarly, the retrotrapezoid nucleus is chemosensitive and may contribute to the hypercapnic ventilatory response ( Guyenet et al, 2016 ).…”