Effect of capsaicin‐sensitive sensory nerves on plasma glucose and catecholamine levels during 2‐deoxyglucose‐induced stress in conscious rats

• Published in: British journal of pharmacology 1990-07, Vol.100 (3), p.523-529
• Main Authors: Zhou, Xin‐Fu, Livett, Bruce G.
• Format: Article
• Language: English
• Subjects: Adrenal Medulla - immunology; Adrenal Medulla - metabolism; Adrenalectomy; Animals; Biological and medical sciences; Blood Glucose - metabolism; Capsaicin - pharmacology; Catecholamines - blood; Denervation; Deoxy Sugars - pharmacology; Deoxyglucose - pharmacology; Fundamental and applied biological sciences. Psychology; Male; Neurons, Afferent - drug effects; Neurons, Afferent - physiology; Peripheral nervous system. Autonomic nervous system. Neuromuscular transmission. Ganglionic transmission. Electric organ; Rats; Rats, Inbred BUF; Splanchnic Nerves - drug effects; Splanchnic Nerves - physiology; Stress, Psychological - physiopathology; Vertebrates: nervous system and sense organs
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1111/j.1476-5381.1990.tb15840.x

1 Sensory fibres innervate the adrenal medulla but their function is not known. In this paper we have studied the effect of capsaicin‐sensitive sensory fibres on the adrenal catecholamine (CA) response and blood glucose response to 2‐deoxyglucose (2‐DG)‐induced glucopenic stress in conscious rats. 2 2‐DG at 500 mg kg−1 (i.v.) induced a 2.5 fold increase in plasma glucose levels, a 3.5 fold increase in inferior vena caval (i.v.c.) plasma noradrenaline (NA) levels and a 7 fold increase in i.v.c. plasma adrenaline (Ad) levels over 60 min. The hyperglycaemia in response to 2‐DG was attenuated by pentolinium and by left splanchnicotomy plus right adrenalectomy. These procedures also caused a complete inhibition of the increase in plasma CA. 3 The hyperglycaemia in response to 2‐DG was attenuated by pretreatment of rats with capsaicin as neonates, suggesting that capsaicin‐sensitive sensory fibres are required for regulation of plasma glucose in response to glucopenic stress. 4 The increase in i.v.c. plasma CA levels in response to 2‐DG during the early phase of glucopenia (first 30 min) in the conscious rats pretreated with capsaicin was the same as in the rats pretreated with vehicle alone. During the later phase of glucopenia (after 45 min), the increase in plasma CA levels in rats pretreated with capsaicin was higher than in the rats pretreated with vehicle alone. 5 In vehicle‐pretreated rats and capsaicin‐pretreated rats the tissue NA and Ad levels in the adrenal medulla after 8 h of stress were depleted to the same extent. However, tissue CA levels in the capsaicin group recovered faster over 24 h than in the vehicle group. 6 These results indicate that capsaicin‐sensitive sensory fibres are not required to maintain adrenal CA secretion during glucopenic stress in the conscious rat but are required for maintenance of blood glucose levels.