Hyperglycaemia produced by intracisternal injection of adrenaline in cats

Abstract

Leimdorfer, Arana & Hack (1947) have shown that in the cat an intracisternal injection of adrenaline produces a long-lasting hyperglycaemia, which they attributed to a central action of the adrenaline. The hyperglycaemia was not reproduced by an intraperitoneal injection of adrenaline. In contrast, the hyperglycaemia produced in the rabbit by the injection of adrenaline into the lateral cerebral ventricle is fuliy accounted for by its absorption into the blood stream, since it is reproduced by intraperitoneal injection and is not affected by bilateral splanchnicotomy (Hasselblatt & Sproull, 1961). It appeared therefore that the hyperglyeaemic response of the cat to intracisternal and of the rabbit to intraventricular adrenaline might result from different mechanisms.However, the present experiments show that one difference between the two species is that, whereas in the rabbit adrenaline given byintraperitoneal injection readily elicits a hyperglycaemic response (Hasselblatt & Sproull, 1961), in the cat it does not. This is not due to a difference in the sensitivity of the two species to the metabolic action of adrenaline because, when infused intravenously, adrenaline is found to be as effective in the cat as in the rabbit. The hyperglyeaemic response of the cat to an intracisternal injection of adrenaline could therefore well be accounted for by absorption.The importance of this mechanism was established in the present experiments by the effect of bilateral splanchnicotomy on the hyperglycaemic response, but a central component, mediated by the splanchnic nerves, was also revealed.According to Leimdorfer (1950), noradrenaline given in small doses by intracisternal injection is, like adrenaline, effective in raising blood glucose concentration. If the hyperglyeaemic effect of intracisternally injected adrenaline or noradrenaline is largely due to systemic absorption noradrenaline should in this respect be the less effective, since it is well known that noradrenaline has a much weaker metabolic action than adrenaline.Previous estimates of the relative hyperglycaemic potency ofnoradrenaline vary greatly, between

An excitatory action of adrenaline, noradrenaline, and 5‐hydroxytryptamine on the spinal cord

“…This is in accord with previous findings that, applied to the inner or outer surfaces of the brain in regions where there is a preponderance of noradrenaline, adrenaline is more potent than noradrenaline; e.g. in the abolition of tremor (Domer & Feldberg, 1960) and reduction of body temperature (Feldberg & Myers, 1964), as well as in the production of somnolence (Feldberg, 1963) and of central hyperglyeaemia (Sproull, 1963).…”

The origin of the hyperglycaemic response to intracisternal adrenaline in the cat: the site of systemic absorption and of central action of adrenaline from the subarachnoid space

“…were obtained. The hyperglycaemia produced by 35-100 ,ug ultimately reached the same or an even higher level than those obtained in previous experiments on intracisternal injection of 50 ,g adrenaline (Sproull, 1963), but developed somewhat more gradually. The distribution of Evans blue placed in the cisterna magna was the same as after its intracisternal injection: the dye spread down the upper cervical cord, around the pons and medulla, through the interpeduncular fossa to the parahypophysial region; no dye was seen on the cerebellar or cerebral cortices.…”

“…4. To explain this variation it is necessary to take into account that the hyperglycaemic response to intracisternal adrenaline consists of two components, absorption into the blood stream and a central action mediated by the splanchnic nerves (Sproull, 1963). The lower curve resembles the response previously obtained on intracisternal injection after bilateral splanchnicotomy, and may therefore be attributed mainly to absorption.…”

“…However, it has recently been shown that this hyperglycaemia is largely attributable to peripheral action following absorption of the adrenaline into the blood stream, although a central component, mediated by the splanchnic nerves, does contribute to the resultant hyperglycaemia (Sproull, 1963).The present experiments, carried out to determine the site or sites of the systemic absorption and of the central action of intracisternally injected adrenaline, have shown that the main sites on and through which adrenaline acts from the subarachnoid space lie in the tuberal region on the ventral surface of the brain. …”

“…However, it has recently been shown that this hyperglycaemia is largely attributable to peripheral action following absorption of the adrenaline into the blood stream, although a central component, mediated by the splanchnic nerves, does contribute to the resultant hyperglycaemia (Sproull, 1963).…”