Chemical sympathectomy and two-way escape and avoidance learning in the rat.

Abstract

Six experiments are reported on the effects of 2,4,5-trihydroxyphenylethylamine (6-hydroxydopamine) on two-way escape and avoidance learning. Rats were tested on either escape or avoidance learning at 80 days of age after chemical sympathectomy at birth or 40 or 80 days of age. Neonatal and chronic sympathectomy (at 40 days), but not acute sympathectomy (at 80 days), resulted in depressed escape learning. Avoidance learning was affected by neonatal sympathectomy and partially by acute sympathectomy. The results have implications for the role of the autonomic nervous system in escape-avoidance learning.

Central catecholamine and peripheral noradrenaline depletion by 6-hydroxydopamine and active avoidance learning in rats.

“…The results showed that central CA depletion did not produce any significant influence on the secretion of resting plasma 11-OHCS levels, and they are in general agreement with the findings of the previous investigators. The findings that peripheral NA depletion produced no significant change in resting plasma 11-OHCS levels are also consistent with the findings of Lord et al (1976) and Martin (1972).…”

“…Both frequency and latency of avoidance are examined for the following reasons. First, it has been shown that acute peripheral depletion of NA reliably results in significantly reduced frequencies of twoway avoidance, but some conflict of data exists with temporal measures (Di Giusto & King, 1972;Lord et al, 1976). Such disparities between frequency and latency measures are important, since they can effectively separate learning from motivational effects.…”

“…Following intracisternal (ic) injection of 6-OHDA at the present dose level, the 14th day seems to be the earliest at which training might safely begin in order to circumvent direct side effects such as aphagia, adipsia, and correlated adjustments in choline acetylase (Ho & Loh, 1972;Smith, Cooper, & Breese, 1973). After ip administration of 6-OHDA in the adult rat at the present dose range, the optimal postinjection delay appears to be about 8 hr (Lord et al, 1976;Malmfors, 1971). In the present experiments we therefore adopted those optimal intervals for studying as nearly as possible the direct influence of neural catecholamine depletion (in the absence of long-term compensatory mechanisms) in adrenergically matured rats.…”

“…In the neonatal studies in which 6-OHDA lesions have been used, a major problem of interpretation stems from the development of compensatory mechanisms (Lord et al, 1976). These compensations derive from an interaction at the time of testing between age and duration of sympathectomy; viz., provided the rat is more than 8 days old when sympathectomized and sufficient time is given between sympathectomy and testing, alternatives may develop to using the damaged adrenergic neurons (Lord et al, 1976; Experiments 2 and 5). Although it is not yet possible to specify the effective compensatory mechanisms (other than that such preparations become better than controls at signaled escape learning), optimal intervals for their evasion have been indicated empirically.…”

Risk factors for rescue analgesic use on the first postoperative day after upper limb surgery performed under single-injection brachial plexus block: a retrospective study of 930 cases

“…A longer duration of surgery was another risk factor for the use of rescue analgesics in the postoperative period. Indeed, lengthy procedures often involve extensive tissue damage, potentially causing an increase in the release of inflammatory mediators [ 16 ]. In addition, a tourniquet is often used in limb surgery to obtain a bloodless field-of-view.…”