Innervation Pattern and Neurogenic Response of Rabbit Veins

Abstract

The adrenergic neuroeffector mechanism has been assessed in 14 different veins of the rabbit chosen to represent vessels of different, function and regional location. The pattern, distribution and density of the adrenergic innervation were assessed by fluorescence histochemistry. The magnitude of the neurogenic contractile response of isolated segments was studied in vitro in relation to the maximum response to 1-norepinephrine. The diameter and wall thickness of the veins was determined. The amount of adrenergic innervation determined histochemically was related to the size of the contractile response. Both fluorescence and response were absent in the superficial cervical, femoral, subcutaneous from back, brachial and deep circumflex iliac branch veins. The amount of adrenergic innervation increased in order in the renal, inferior vena cava, pulmonary, jugular, parietal branch of internal iliac, mesenteric, central ear, cephalic and small saphenous veins. In the latter two veins, innervation was not restricted to the adventitio-medial junction but entered the media. The pattern of innervation and contractile response may be related to the functional need for active venoconstriction in the various parts of the capacitance section of the vascular system.

Feline cerebral veins and arteries: comparison of autonomic innervation and vasomotor responses

“…However, the magnitude of responses of the veins to VIP was small (Table 3 vation displays marked differences (Bevan, Hosmer, Ljung, Pegram & Su, 1974;Shepherd & Vanhoutte, 1975;Bevan et al 1980). In the cutaneous and splanchnic circulations the veins are innervated densely by noradrenergic nerve fibres, whereas the veins draining skeletal muscle contain only a few nerve fibres (Fuxe & Sedvall, 1965;Bevan et al 1974;Shepherd & Vanhoutte, 1975 nerve fibres, and thus confirms the earlier, brief description of cerebral venous noradrenergic innervation (Nielsen & Owman, 1967), although the present observations point to a more abundant innervation density than the scarce innervation noted by these authors. Noradrenaline effects constriction of veins in most peripheral vascular beds, and this action appears to be mediated via a-adrenoreceptors (Shepherd & Vanhoutte, 1975;Altura, 1978;Bevan et al 1980); the present observations in the cerebral circulation are thus in consistent agreement with those from peripheral vascular beds.…”

Potentiation in various agonists-induced contractions of rabbit mesenteric artery by sulfhydryl reagents.

“…However, the regional differences of rabbit arteries in the responses to sulfhydryl reagents have never been described. It is well known that the vasculature exhibits a marked heterogeneity (26)(27)(28), therefore there is a need for caution when extrapolating data on the aorta to other vascular tissues. In the present study, we demonstrated that at least in the rabbit mesenteric artery, the contractile responses to all the agonists used were potentiated by sulfhydryl reagents.…”

Abnormal innervation of lower limb epineurial arterioles in human diabetes

“…The extent of neuronal influence on vascular smooth muscle is largely determined by the transmitter concentration at the smooth muscle cell membrane [1,23]. At a narrow neuromuscular cleft the released transmitter has to travel over only a short distance and therefore remains concentrated, whereas in a wide cleft the transmitter becomes less concentrated due to diffusion as 'it travels towards the smooth muscle ceil.…”

“…Several in vitro studies have indicated that vasomotor function, in particular the response of blood vessels to sympathetic nerve stimulation, is significantly decreased in the presence of widened distances between nerve terminals and vascular smooth muscle cells, especially if the increased nerve-muscle distance is coupled with decreased density of innervation [1,18,23]. Bevan has suggested that the greatest neuromuscular interval across which a biologically effective transmitter concentration is maintained is 6 grn [3].…”