The subcellular localization and release of the molluscan neuro-peptide Phe-Met-Arg-Phe-NH(,2) (FMRFamide) from ganglia of the marine mollusc, Macrocallista nimbosa, was examined. Ganglia were pooled, homogenized and subjected to differential centrifugation. FMRFamide was concentrated in the microsomal pellet. When the medium-speed supernatant was centrifuged in a discontinuous sucrose gradient, three separate peaks of activity were detected and identified as acetylcholine (ACh), 5-hydroxytryptamine (5-HT) and FMRFamide. The relative concentration of FMRFamide in each fraction was determined by bioassay and by radioimmunoassay (RIA). Both determinations revealed a peak of peptide in the middle of the sucrose gradient. Electron micrographs of each of the gradient interfaces were analyzed. The interface containing the peak of biological FMRFamide activity was enriched two- to five-fold in neurosecretory granules with a mean diameter of 104 nm and various electron densities. Morphologically similar vesicles were also seen in intact ganglia. / Macrocallista ganglia were pooled and incubated in a series of seawater media. Release of immunoreactive FMRFamide into the media was enhanced two to seven times by exposure to a high potassium medium, and was reversibly inhibited by removal of the external calcium from the high potassium medium. Immunoreactive FMRFamide was present in Macrocallista hemolymph at a concentration (10('-9) M) that excites isolated Macrocallista ventricles. These findings strongly suggest that FMRFamide functions as a neurohormone or neurotransmitter in Macrocallista. / The effects of catecholamines, 5-HT and phenylethylamines on the isolated radula protractor muscle of Busycon contrarium were examined. FMRFamide, ACh and dopamine (DA) act at separate excitatory receptors. DA elicits a phasic contraction of the muscle that is rapidly desensitized by repeated high doses of DA. The actions of FMRFamide, ACh and DA are sodium-dependent; FMRFamide is more calcium-dependent than ACH or DA. 5-HT, DA and the phenylethylamines can relax muscles contracted by FMRFamide and ACh, possibly by acting at separate receptor sites, or at sites of action common to the amines. / Source: Dissertation Abstracts International, Volume: 42-07, Section: B, page: 2723. / Thesis (Ph.D.)--The Florida State University, 1981.

Source: Dissertation Abstracts International, Volume: 41-01, Section: B, page: 0085. / Thesis (Ph.D.)--The Florida State University, 1979.

The effects of altering skin and core temperature by cold exposure and exercise on substrate mobilization and utilization were examined. Six subjects between the ages of 22-27 years rested and exercised in neutral and cold environments to produce (1)a neutral core and neutral skin temperature, (2)a neutral core and cold skin temperature, and (3)a cold core and cold skin temperature. Free fatty acid (FFA), glucose (GL), lactate (LA), hemoglobin (Hb), and hematocrit (Hct) concentration were measured after 30, 60, and 90 minutes of exposure to three temperature conditions during rest and three conditions during exercise. In addition, heart rate (HR), respiratory quotient (RQ), and oxygen consumption (VO(,2)) were analyzed during the same time period. Analysis of variance(' ) with repeated measures was used to determine the significance of the effects of skin and core temperatures on the variables of interest. The results indicated that FFA, GL, LA, Hb, and Hct, concentration significantly increased during rest when both mean skin temperature (T(,sk)) and rectal temperature (T(,re)) were reduced. Plasma FFA(' ) concentration was also significantly elevated during exercise when both T(,sk) and T(,re) were lowered. No significant differences were observed when(' ) T(,sk) alone reduced. HR decreased and VO(,2) increased during rest when(' ) T(,sk) and T(,re) reduced but during exercise HR was reduced when T(,sk)(' ) alone was lowered. No significant difference was demonstrated between thermoregulatory VO(,2) during exercise and thermoregulatory VO(,2)(' ) during rest when comparing absolute values. However, when comparing the relative changes during each condition, greater increases were observed in thermoregulatory VO(,2) during rest than during exercise. A significant(' ) inverse correlation was observed between thermoregulatory VO(,2) and(' ) the increase in / FFA concentration during rest in the cold when T(,sk) alone(' ) was lowered. RQ values decreased during exercise in the cold when both T(,sk) and T(,re) were reduced. It was concluded that reductions in both T(,sk)(' ) and T(,re) are necessary during cold exposure to produce increases in substrates, hemoconcentration, lactate, and VO(,2). In addition, fat(' ) mobilization and utilization occurs during exercise in the cold only if reductions in both T(,sk) and T(,re) are produced. Light exercise may inhibit(' )the relative increase in thermogenesis during cold exposure but not whencomparing absolute values at a given time period. An inverse relationshipbetween thermogenesis and fat mobilization occurs during rest in the cold(, )when T(,sk) is reduced. / Source: Dissertation Abstracts International, Volume: 42-03, Section: B, page: 0928. / Thesis (Ph.D.)--The Florida State University, 1981.

Source: Dissertation Abstracts International, Volume: 32-12, Section: B, page: 7285. / Thesis (Ph.D.)--The Florida State University, 1971.

Source: Dissertation Abstracts International, Volume: 36-01, Section: B, page: 0115. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 37-10, Section: B, page: 4903. / Thesis (Ph.D.)--The Florida State University, 1976.

Source: Dissertation Abstracts International, Volume: 35-10, Section: B, page: 5071. / Thesis (Ph.D.)--The Florida State University, 1974.

Source: Dissertation Abstracts International, Volume: 36-02, Section: B, page: 0593. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 36-12, Section: B, page: 5991. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 36-12, Section: B, page: 5997. / Thesis (Ph.D.)--The Florida State University, 1975.