The sympatho-adrenergic response in hyperthermia.

The sympatho-adrenergic reaction was investigated in heated rats under the influence of a ganglioblocking agent--hexamethonium. The overheating at a 40 degrees environmental temperature produced in a relatively short interval (after 157 min on an average) the death of the animals. An initial bradycardia was followed by a tachycardic phase.

Hypergravitation and sympatho-adrenergic reactivity.

The sympatho-adrenergic reaction of the organism subjected to hypergravitation was investigated in rats exposed to +6 Gz. The electro- and cardiotachograms recorded telemetrically were correlated with the adrenal catecholamine content. The determinations were made in controls and in rats treated with hexamethonium and atropine administered separately or together.

The role of the sympathoadrenergic reaction in adaptation of the organism to the action of + 6 Gz acceleration.

In experiments on rats the symphathoadrenergic reactivity after a + 6 Gz acceleration was investigated. Hypergravitation produced as a rule a short initial bradycardia, followed by tachycardia. Hexamethonium (C6), a peripheric ganglion-blocking agent, produced bradycardia, diminution or vanishing of the initial bradycardic episode, and a decreased tachycardic reaction.