[Effects of substance P and its fragments in physiological and pathological pain]. / Vliianie substantsii P i ee fragmentov na fiziologicheskuiu i patologicheskuiu bol'.

It has been shown that substance P and its fragments can produce under certain conditions an analgetic effect on both physiological and pathological pain (i.e. on pain syndrome of spinal origin). The data obtained give evidence that prolonged hypoalgesia is caused by the injection of substance P and its fragments to nucleus raphe dorsal--a structure of the antinociceptive system. This analgetic effect can be initiated by the activation of the antinociceptive system influenced by substance P and or its fragments.

[Effect of the N-terminal fragment of substance P on the microcirculatory system]. / Vliianie N-kontsevogo fragmenta veshchestva P na sistemu mikrotsirkuliatsii.

Biomicroscopic experiments have shown that the N-terminal fragment of substance P (SP1-4), when applied to the rat mesentery, has a considerably lower injuring effect than substance P (SP1-11) itself. SP1-4 activity, as compared to SP1-11 activity regarded as 1, was 0.007 in case of microcirculatory disturbances and venular permeability increase and 0.0007 in case of mast cell degranulation increase. The data obtained suggest that the slightest damaging effect of SP1-4 on microcirculation is combined with anti-stress activity.

[Comparative study of substance P and its fragments: analgesic properties, effect on behavior and monoaminergic processes]. / Sravnitel'noe izuchenie veshchestva P i ego fragmentov: anal'geticheskie svoistva, vliianie na povedenie i monoaminergicheskie protsessy.

The effect of substance P (SP) and of its fragments 5-11, 8-11, 9-11, 10-11 administered into the brain ventricles in doses of 5, 25 and 50 nM on the behavior and content of biogenic monoamines of the rat brain was studied. The analgetic properties of the substances under consideration and those of fragment SP 10-11 in doses of 5, 25, 50 and 100 nM were also subjected to examination. It was found that SP and fragment 5-11 stimulate and enhance the locomotor activity in rats, while fragments 8-11 and 9-11 provoke hypoactivity. The substances under study increase the serotonin and dopamine turnover, whereas SP and fragment 8-11 lower the serotonin content as well. After administration of SP and fragment 5-11 analgesia was seen to transform to hyperalgesia depending on the dose. Fragments 8-11 and 9-11 produce analgetic effect. It is suggested that both SP fragments and the whole SP molecule can influence the neurochemical process that regulate behavior and pain perception.