EFFECTS OF THE EXTRADURAL ADMINISTRATION OF MORPHINE OR BUPIVACAINE, ON THE METABOLIC RESPONSE TO UPPER ABDOMINAL SURGERY

The influence of thoracic extradural local anaesthetics (0.5%bupivacaine) or extradural morphine on the metabolic responseto upper abdominal surgery was compared with the administrationof morphine i.v. in the period after operation. The extradurallocal anaesthetic group had significantly lower blood glucoseand plasma FFA concentrations and consistently, but not significantly,lower blood glycerol and lactate concentrations than both theother groups. At 4 h both extradural groups had significantlylower plasma FFA and blood 3-hydroxybutyrate concentrationsthan the control group. Blood alanine concentration decreasedin all three groups with a minimum at 24 h. There were no differencesin serum insulin concentrations between the groups. It is concludedthat thoracic extradural morphine differs from thoracic extradurallocal anaesthetics in being much less able to suppress the metabolicresponse associated with upper abdominal surgery.     

Pituitary adenylate cyclase activating peptide (PACAP) in salivary glands of the rat: origin,and secretory and vascular effects

Pituitary adenylate cyclase activating peptide (PACAP)-38. injected Lv. to the anaesthetized rat. evoked secretion of saliva from the three major salivary glands. the submandibular glands responding with the greatest and the sublingual glands with the smallest volumes. The parotid saliva was rich in amylase and protein. In vitro. pieces of parotid and submandibular gland tissues released K⁺ and protein in response to PACAP-38. with atropine and adrenoceptor antagonists present. The blood flow in the submandibular gland increased in response to PACAP-38. despite a marked fall in mean aortic blood pressure. PACAP is a vasoactive intestinal peptide (VIP)-like neuropeptide. A comparison between the two peptides showed PACAP-38 to be more effective than VIP with respect to vascular responses and less or equi-effective with VIP with respect to the secretory responses. thus suggesting the involvement of PACAP type I and type II receptors. respectively PACAP-38 and -27 were present in the parotid gland as judged by radioimmunoassay. the concentration of the former being about twice that of the latter. Parasympathetic denervation. by cutting the auricula-temporal nerve. reduced the total parotid gland contents of PACAP-38 and -27 by 23 and 44%. respectively (compared with a previously demonstrated 95% reduction of VIP). Sympathetic de nervation. section of the facial nerve or treatment with the sensory neurotoxin capsaicin did not affect the content of PACAP. The difference in efficacy between PACAP and VIP in the vascular and secretory responses as well as the difference in localization suggest that the two peptides play different physiological roles in the salivary glands.     

EFFECTS OF THE EXTRADURAL ADMINISTRATION OF MORPHINE, OR BUPIVACAINE, ON THE ENDOCRINE RESPONSE TO UPPER ABDOMINAL SURGERY

The endocrine response, and the relief of pain, following theextradural administration of morphine or a local anaestheticagent bupivacaine (0.5%) were studied for 24 h after abdominalsurgery and compared with a control group given conventionali.v. morphine after operation. Samples were taken before andat 2, 4, 6, 12 and 24 h after skin incision. Pain relief inboth extradural groups was significantly better when comparedwith the control group. In all three groups, the plasma concentrationof cortisol was increased immediately after surgery. Thereafter,significantly lower values were seen in the extradural groups.Plasma adrenaline concentration was lower immediately aftersurgery only in the group given the extradural local anaesthetic.Plasma noradrenaline concentration remained unchanged afterextradural local anaesthesia while an intermediate increaseoccurred after extradural morphine. Plasma noradrenaline concentrationwas significantly greater in the controls compared with bothextradural groups. Our results indicate that extradural analgesiawith a local anaesthetic drug can suppress the increases inthe plasma concentrations of the catecholamines and cortisolafter surgery. In contrast to extradural local anaesthetic extraduralmorphine cannot suppress the endocrine response immediatelyafter surgery. However, later in the postoperative period, extraduralmorphine can suppress the endocrine response, thus indicatingthat postoperative pain is a factor involved in the stress responsefollowing surgery.