No abstract

SU-MMARY 1. The gastric mucosal blood flow has been measured by the amidopyrine clearance technique in anaesthetized cats. The total gastric blood flow has been (a) measured directly and (b) calculated by the Fick principle from the amidopyrine concentrations in gastric arterial and venous blood and the gastric output of amidopyrine.2. Observations on the recovery of added amidopyrine from arterial and venous blood and plasma, and on the rate of transfer of amidopyrine from corpuscles to plasma, support the underlying assumptions of the amidopyrine method of measuring mucosal blood flow.3. If acid solutions are instilled into the stomach the mucosal blood flow of the non-secreting stomach may be measured by the amidopyrine technique.4. Total gastric and mucosal blood flow increased linearly with increase in H+ secretion, stimulated by histamine or gastrin. The increase in total flow was entirely due to the increase in mucosal flow.5. The relationship between mucosal blood flow and H+ secretion was the same for histamine and gastrin responses, and was unaffected by maintaining the total flow at a constant level, or by reduction of the circulating blood volume. Increase in blood volume altered the relationship so that there was a greater increment in mucosal blood flow for any increase in H+ secretion.6. It is concluded that valid observations may be made on secretion and blood flow relationships in acute anaesthetized preparations.

The two major categories of factors known to influence adult sexual behavior potentials are the relative amounts of androgen present during specific stages of perinatal ontogeny and adequate social stimulation during prepuberal development. The possible interaction between these two was evaluated by characterizing the ejaculatory and lordotic behavior potentials of prenatally stressed and control male rats that had been weaned at 16 days of age and raised either in total social isolation or with a same-age female, a control male, or a prenatally stressed male. The decrement in male sexual behavior produced by prenatal stress was attenuated by raising the male with either a female or a control male. Social isolation alone or in combination with stress resulted in severely deficient male behavior. Peripheral skin shock promoted ejaculatory behavior in many previously noncopulating prenatally stressed males raised with other stressed males, but it was ineffective in most isolated animals. The high lordosis potential characteristic of prenatally stressed male rats was slightly lower in the group with a female cagemate and was markedly decreased by social isolation. These results support and extend the finding by Dunlap, Zadina, and Gougis (1978) that prenatal hormonal events and prepuberal rearing conditions can interact to attenuate or accentuate the effects that either treatment alone has on the development of adult sexual behavior potentials.

SUMMARY1. Electrical stimulation of the vagus nerves produced a parallel increase in gastric acid secretion and gastric mucosal blood flow.2. Gastric acid secretion and mucosal blood flow, stimulated by pentapeptide infusions or by vagal stimulation, were markedly and equally reduced by electrical stimulation of splanchnic nerve fibres.3. The splanchnic stimulated reduction in acid and mucosal blood flow occurred only when the rise in blood pressure, normally associated with splanchnic stimulation, was prevented by inclusion of a pressure reservoir in the circulation.4. There was evidence that the effect of the splanchnic nerves was not mediated by release of adrenaline from the adrenal medulla.

(-32.0,uequiv H+ kg-' 15 min-'). This is followed by a slow phase of tachyphylaxis (-9-4 ,equiv H+ kg-' 15 min-') up to 5 hr of stimulation.

SUMMARY1. Chloralose anaesthetized cats were prepared with fundic and antral pouches. Fundic mucosal blood flow was measured by the amidopyrine technique and serum gastrin was measured by radioimmunoassay.2. Meat extract suspension in the pyloric antrum produced a highly significant sixfold increase in arterial serum gastrin concentration (P < 0-001).3. The mean ratio of the fundic mucdsal blood flow to acid secretary responses (AMBF/LAH+ ratio) of 0-142 + 0-026 (25) ml./,uequiv H+, is very similar to the values previously published for exogenous gastrin stimulation. 4. Splanchnic nerve stimulation, during responses to meat extract stimulation, produced significant reductions in gastric acid secretion (P < 0-025), fundic mucosal blood flow (P < 0-02), arterial serum gastrin concentration (P < 0-01) and gastrin delivered to the mucosa (P < 0.001).5. In the 30 min period following the end of splanchnic nerve stimulation only arterial serum gastrin concentration remained significantly reduced.

SUMMARY1. Gastric mucosal blood flow (MBF) and gastric acid secretion have been compared and related during the infusion of a wide dose range of gastrin extracts, pentapeptide (Peptavlon, I.C.I. 50123) and histamine.2. Constancy of increase in mucosal blood flow relative to H+ secretion was obtained with gastrin stimulation, whereas histamine stimulation produced higher ratios of mucosal blood flow to H+ secretion, and these ratios declined as each experiment continued.3. The importance of considering only the increase in mucosal blood flow in relation to acid secreted is demonstrated.4. It is concluded that the differences shown in the AMBF/AH+ with histamine and gastrin stimulation provide further evidence that the amidopyrine clearance technique measures gastric mucosal blood flow.

3. The inhibition of pentagastrin stimulated acid and pepsin secretion by Somatostatin delays the tachyphylaxis of these responses, but the rates of tachyphylaxis when they do subsequently occur are identical.4. Metiamide 1O mg. kg-'. hr-' equally inhibits histamine and pentagastrin stimulated acid secretion but does not inhibit pentagastrin stimulated pepsin secretion.5. Inhibition of acid secretion during metiamide infusion neither prevents nor delays acid nor pepsin tachyphylaxis.6. It is suggested that tachyphylaxis of acid and pepsin secretion is a gastrin receptor phenomenon and that Somatostatin occupies or modifies the behaviour of these receptors, preventing tachyphylaxis. Metiamide, however, exerts its action only on the histamine H2-receptor and not the gastrin receptor mechanism, and this apparently does not prevent or delay acid tachyphylaxis.