An investigation of the role of adrenergic innervation in the regulation of the extraneuronal uptake of [³H]‐isoprenaline into rat vasa deferentia and atria

Abstract

3 The appearance and subsequent development of extraneuronal uptake in embryonic and newborn rats did not appear to be dependent on a fully developed or functional adrenergic innervation. 4 Decreasing plasma catecholamine levels by adrenal demedullation did not have an effect on extraneuronal uptake. 5 Chronic cold exposure (7 days) significantly increased plasma levels of adrenaline, and there was a significant decrease in the corticosterone-sensitive extraneuronal uptake of [3H]-isoprenaline into atria. After 14 days in the cold, plasma adrenaline levels had fallen, and were no longer significantly different from control levels. 6 The extraneuronal uptake of [3H]-isoprenaline into atria after 14 days cold exposure was no longer different from that of control atria. There did not appear to be a direct correlation between plasma catecholamines and extraneuronal accumulation of [3H]-isoprenaline. 7 Neither the presence of adrenergic nerves nor plasma catecholamines appear to play a major role in the regulation of extraneuronal uptake by atria and vasa deferentia of the rat.

A role for corticosterone in the in vivo regulation of the extraneuronal uptake of [3H]‐isoprenaline into rat atria

“…reserpine treatment and cold-exposure (7 days) resulted in a similar increase in plasma corticosterone, the decrease in extraneuronal uptake in atria from reserpine treated rats (64%) was larger than that measured in atria from cold-exposed rats (25%) (Morton, 1987). Similarly, both hypophysectomy and adrenalectomy reduced corticosterone levels to the same extent, yet the increase in extraneuronal uptake seen after hypophysectomy (32%) was greater than that measured after adrenalectomy (20%).…”

“…This decrease was due to the timedependent loss of a corticosterone-sensitive component of extraneuronal uptake. However, whilst it is not clear what causes this change, the extraneuronal uptake does not appear to be dependent upon either the presence of the adrenergic neurone or the level of circulating catecholamines (Morton, 1987). Thus some other factor altered by reserpine treatment is implicated in the regulation of the extraneuronal uptake.…”

“…Extraneuronal uptake was measured as previously described (Morton, 1987). Briefly, uptake was calculated as the difference between accumulation of…”

Kinetic Studies on Uptake of Serotonin and Noradrenaline into Pial Arteries of Rats

“…Taking advan tage of the well-known sympathetic innervation of cerebral vessels (Nielsen and Owman, 1967), we used superior cervical ganglionectomy as the blank. The difference between data from intact and gan glionectomized groups of animals is attributed only to the sympathetic uptake of the amines, because the de nervation has no important influence on the nonneurogenic uptake process (Gillespie et aI., 1970;Morton, 1987). As the origin and distribution of the sympathetic innervation in the lower part of the basilar artery and vertebral artery may vary in individual animals, even from one and the same species (Kajikawa, 1968(Kajikawa, , 1969Cowen et aI., 1987;Arbab et aI., 1988;Chang et aI., 1989), this portion of pial vessels was excluded from the uptake studies to improve the accuracy of the analysis.…”