Drug Effects on Pre‐and Post‐branchial Blood Pressure and Heart Rate in a Free‐swimming Marine Teleost, Gadus morhua 1

• Published in: Acta Physiologica Scandinavica
• Main Authors: Helgason, Sigurdur St., Nilsson, Stefan
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1973
• Subjects: Gadus morhua
• Online Access: http://dx.doi.org/10.1111/j.1748-1716.1973.tb05482.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-1716.1973.tb05482.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-1716.1973.tb05482.x

Abstract Drug effects on pre‐and post‐branchial blood pressure and heart rate have been simultaneously and continuously registrated in free‐swimming cod (Gadus morhua). Adrenaline, noradrenaline and phenylephrine increased blood pressure, presumably by increasing systemic vascular resistance by alpha adrenergic stimulation. The heart rate was decreased by the same drugs, obviously by a baro‐receptor reflex, with the efferent inhibitory cholinergic fibres running in the vagus nerve. Yohimbine decreased the blood pressure and blocked the effect of adrenaline. The drop in blood pressure may be due to blockade of a normally acting vaso‐constrictor effect on the systemic vessels. Pre‐and post‐branchial blood pressure was reduced by isoprenaline, and this effect was reversed by propranolol, suggesting presence of adrenergic beta‐receptors in the systemic vascular bed. Propranolol also caused a drop in heart rate and post‐branchial blood pressure, while the pre‐branchial blood pressure was increased. This again could be due to abolishment of a normally acting adrenergic influence on the heart and branchial vessels.