Caffeine Ingestion by Rats Increases Noradrenaline Turnover and Results in Self-Biting

Normally, caffeine ingestion results in a wide spectrum of neural and hormonal responses, making it difficult to evaluate which are critical regulatory factors. We examined the responses to caffeine (6 mg/kg) ingestion in a group of spinal cord-injured subjects [7 tetraplegic (C5–7) and 2 paraplegic (T4) subjects] at rest and during functional electrical stimulation of their paralyzed limbs to the point of fatigue. Plasma insulin did not change, caffeine had no effect on plasma epinephrine, and there was a slight increase ( P < 0.05) in norepinephrine after 15 min of exercise. Nevertheless, serum free fatty acids were increased ( P < 0.05) after caffeine ingestion after 60 min of rest and throughout the first 15 min of exercise, but the respiratory exchange ratio was not affected. The exercise time was increased ( P < 0.05) by 6% or 1.26 ± 0.57 min. These data suggest that caffeine had direct effects on both the adipose tissue and the active muscle. It is proposed that the ergogenic action of caffeine is occurring, at least in part, by a direct action of the drug on muscle.

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Effects of Caffeine Ingestion on Utilization of Muscle Glycogen and Lipid During Leg Ergometer Cycling

International Journal of Sports Medicine ◽

10.1055/s-2008-1034637 ◽

1980 ◽

Vol 01 (02) ◽

pp. 86-90 ◽

Cited By ~ 112

Author(s):

D. Essig ◽

D. Costill ◽

P. Van Handel

Keyword(s):

Muscle Glycogen ◽

Caffeine Ingestion ◽

Ergometer Cycling

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Antioestrogen inhibition of oestradiol-induced alterations in hypothalamic noradrenaline turnover

Journal of Endocrinology ◽

10.1677/joe.0.1060037 ◽

1985 ◽

Vol 106 (1) ◽

pp. 37-42 ◽

Cited By ~ 5

Author(s):

C. Hiemke ◽

B. Poetz ◽

R. Ghraf

Keyword(s):

Brain Area ◽

Serum Levels ◽

Ovariectomized Rats ◽

Noradrenaline Turnover ◽

Stimulatory Action ◽

Enhanced Sensitivity ◽

Oestradiol Benzoate ◽

Lh Release ◽

Secretory System

ABSTRACT Long-term (4–6 weeks) ovariectomized rats were injected with either oestradiol benzoate (OB; 20 μg s.c.) or monohydroxytamoxifen (MTAM; 0·2 mg i.p.) plus OB. Oestradiol benzoate was administered at 12.00 h on day 0 and MTAM was given immediately before OB, followed by further injections twice daily to maintain sufficiently high antioestrogen levels. When given alone, OB reduced the serum levels of LH during the morning (08.00–09.00 h) and afternoon (17.30–18.30 h) hours of day 3 after priming. The feedback actions of OB on LH release were accompanied by time-dependent alterations of noradrenaline turnover in the preoptic–anterior hypothalamic brain area (POAH). On day 3 after priming the noradrenaline turnover rate was reduced in the morning and increased in the afternoon. The increase correlated with an enhanced sensitivity of the LH secretory system to progesterone. The antioestrogen MTAM blocked the OB-induced sensitization of LH release to the stimulatory action of progesterone and interfered with the stimulatory long-term effect of oestradiol on hypothalamic noradrenaline turnover. The data strongly support the view that the oestrogen-induced afternoon increase of noradrenaline turnover in the POAH represents a pre-requisite for the induction of LH surges. The stimulatory effect of oestradiol on hypothalamic noradrenaline turnover seems to be mediated by a classical oestrogen receptor mechanism. J. Endocr. (1985) 106, 37–42

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Effect of Caffeine on Leg-Muscle Pain during Intense Cycling Exercise: Possible Role of Anxiety Sensitivity

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.18.2.103 ◽

2008 ◽

Vol 18 (2) ◽

pp. 103-115 ◽

Cited By ~ 27

Author(s):

Rachael C. Gliottoni ◽

Robert W. Motl

Keyword(s):

Pain Intensity ◽

Anxiety Sensitivity ◽

High Intensity ◽

Muscle Pain ◽

Caffeine Ingestion ◽

Cycling Exercise ◽

College Age ◽

Peak Aerobic Capacity ◽

Leg Muscle

This experiment examined the effect of a moderate dose of caffeine on perceptions of leg-muscle pain during a bout of high-intensity cycling exercise and the role of anxiety sensitivity in the hypoalgesic effect of caffeine on muscle pain during exercise. Sixteen college-age women ingested caffeine (5 mg/kg body weight) or a placebo and 1 hr later completed 30 min of cycling on an ergometer at 80% of peak aerobic capacity. The conditions were completed in a counterbalanced order, and perceptions of leg-muscle pain were recorded during the bouts of exercise. Caffeine resulted in a large reduction in leg-muscle pain-intensity ratings compared with placebo (d = −0.95), and the reduction in leg-muscle pain-intensity ratings was larger in those with lower anxiety-sensitivity scores than those with higher anxiety-sensitivity scores (d = −1.28 based on a difference in difference scores). The results support that caffeine ingestion has a large effect on reducing leg-muscle pain during high-intensity exercise, and the effect is moderated by anxiety sensitivity.

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Age related changes in noradrenaline, noradrenaline turnover and adrenaline in brainstem nuclei of wistar kyoto and spontaneously hypertensive rats

Neurochemistry International ◽

10.1016/0197-0186(88)90170-2 ◽

1988 ◽

Vol 12 (3) ◽

pp. 315-322

Author(s):

E.L. Conway ◽

W.J. Louis

Keyword(s):

Spontaneously Hypertensive Rats ◽

Hypertensive Rats ◽

Noradrenaline Turnover ◽

Spontaneously Hypertensive ◽

Age Related ◽

Brainstem Nuclei ◽

Wistar Kyoto ◽

Age Related Changes

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Acute effects of caffeine ingestion at rest in humans with impaired epinephrine responses

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.3.999 ◽

1996 ◽

Vol 80 (3) ◽

pp. 999-1005 ◽

Cited By ~ 43

Author(s):

M. Van Soeren ◽

T. Mohr ◽

M. Kjaer ◽

T. E. Graham

Keyword(s):

Blood Pressure ◽

Adenosine Receptors ◽

Vascular Tissue ◽

Physiological Responses ◽

Acute Effects ◽

Peripheral Vascular ◽

Direct Stimulation ◽

Spinal Cord Lesions ◽

Caffeine Ingestion ◽

Stimulation Of

Caffeine ingestion has been demonstrated to increase circulating epinephrine (Epi) and norepinephrine (NE), elevate free fatty acids (FFAs), and alter heart rate, blood pressure (BP), and ventilation in humans. Whether these physiological responses are a result of caffeine acting through direct stimulation of specific tissues via adenosine receptors or secondary to Epi increases is not known. In the present experiment, six tetraplegics (level of spinal cord lesions C4-C6) were tested at rest for 3 h to investigate the effects of 6 mg/kg caffeine in capsule form on subjects with impaired Epi responses. Ventilatory, cardiovascular, metabolic, and hormonal data were collected every 15-20 min after caffeine ingestion. There were no significant (P > 0.05) increases in plasma Epi after caffeine ingestion [0.19 +/- 0.04 (SE) nM (preingestion); 0.20 +/- 0.04 nM (80 min postingestion)] or in plasma NE [0.53 +/- 0.16 nM (preingestion); 0.49 +/- 0.09 nM (80 min postingestion; P > 0.05)]. However, significant increases were found in serum FFAs [0.53 +/- 0.08 nM (preingestion); 1.03 +/- 0.20 mM (40 min postingestion; P < 0.05] and in glycerol. These concentrations remained elevated throughout the experiment. BP increased in the first hour postingestion. These data demonstrate that caffeine in physiological doses directly stimulates specific tissues, i.e., adipose and peripheral vascular tissue, and these effects are not secondary to increases in Epi after caffeine ingestion.

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